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 uint64_t dev_offset; 81 uint64_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 *tlsauthz; 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, "export name", errp) < 0) { 442 return -EIO; 443 } 444 name[client->optlen] = '\0'; 445 client->optlen = 0; 446 447 trace_nbd_negotiate_handle_export_name_request(name); 448 449 client->exp = nbd_export_find(name); 450 if (!client->exp) { 451 error_setg(errp, "export not found"); 452 return -EINVAL; 453 } 454 455 trace_nbd_negotiate_new_style_size_flags(client->exp->size, 456 client->exp->nbdflags | myflags); 457 stq_be_p(buf, client->exp->size); 458 stw_be_p(buf + 8, client->exp->nbdflags | myflags); 459 len = no_zeroes ? 10 : sizeof(buf); 460 ret = nbd_write(client->ioc, buf, len, errp); 461 if (ret < 0) { 462 error_prepend(errp, "write failed: "); 463 return ret; 464 } 465 466 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 467 nbd_export_get(client->exp); 468 nbd_check_meta_export(client); 469 470 return 0; 471 } 472 473 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 474 * The buffer does NOT include the info type prefix. 475 * Return -errno on error, 0 if ready to send more. */ 476 static int nbd_negotiate_send_info(NBDClient *client, 477 uint16_t info, uint32_t length, void *buf, 478 Error **errp) 479 { 480 int rc; 481 482 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 483 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 484 sizeof(info) + length, errp); 485 if (rc < 0) { 486 return rc; 487 } 488 info = cpu_to_be16(info); 489 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 490 return -EIO; 491 } 492 if (nbd_write(client->ioc, buf, length, errp) < 0) { 493 return -EIO; 494 } 495 return 0; 496 } 497 498 /* nbd_reject_length: Handle any unexpected payload. 499 * @fatal requests that we quit talking to the client, even if we are able 500 * to successfully send an error reply. 501 * Return: 502 * -errno transmission error occurred or @fatal was requested, errp is set 503 * 0 error message successfully sent to client, errp is not set 504 */ 505 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 506 { 507 int ret; 508 509 assert(client->optlen); 510 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length", 511 nbd_opt_lookup(client->opt)); 512 if (fatal && !ret) { 513 error_setg(errp, "option '%s' has unexpected length", 514 nbd_opt_lookup(client->opt)); 515 return -EINVAL; 516 } 517 return ret; 518 } 519 520 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 521 * Return -errno on error, 0 if ready for next option, and 1 to move 522 * into transmission phase. */ 523 static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags, 524 Error **errp) 525 { 526 int rc; 527 char name[NBD_MAX_NAME_SIZE + 1]; 528 NBDExport *exp; 529 uint16_t requests; 530 uint16_t request; 531 uint32_t namelen; 532 bool sendname = false; 533 bool blocksize = false; 534 uint32_t sizes[3]; 535 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 536 537 /* Client sends: 538 4 bytes: L, name length (can be 0) 539 L bytes: export name 540 2 bytes: N, number of requests (can be 0) 541 N * 2 bytes: N requests 542 */ 543 rc = nbd_opt_read_name(client, name, &namelen, errp); 544 if (rc <= 0) { 545 return rc; 546 } 547 trace_nbd_negotiate_handle_export_name_request(name); 548 549 rc = nbd_opt_read(client, &requests, sizeof(requests), errp); 550 if (rc <= 0) { 551 return rc; 552 } 553 requests = be16_to_cpu(requests); 554 trace_nbd_negotiate_handle_info_requests(requests); 555 while (requests--) { 556 rc = nbd_opt_read(client, &request, sizeof(request), errp); 557 if (rc <= 0) { 558 return rc; 559 } 560 request = be16_to_cpu(request); 561 trace_nbd_negotiate_handle_info_request(request, 562 nbd_info_lookup(request)); 563 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 564 * everything else is either a request we don't know or 565 * something we send regardless of request */ 566 switch (request) { 567 case NBD_INFO_NAME: 568 sendname = true; 569 break; 570 case NBD_INFO_BLOCK_SIZE: 571 blocksize = true; 572 break; 573 } 574 } 575 if (client->optlen) { 576 return nbd_reject_length(client, false, errp); 577 } 578 579 exp = nbd_export_find(name); 580 if (!exp) { 581 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 582 errp, "export '%s' not present", 583 name); 584 } 585 586 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 587 if (sendname) { 588 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 589 errp); 590 if (rc < 0) { 591 return rc; 592 } 593 } 594 595 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 596 * client request */ 597 if (exp->description) { 598 size_t len = strlen(exp->description); 599 600 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 601 len, exp->description, errp); 602 if (rc < 0) { 603 return rc; 604 } 605 } 606 607 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 608 * according to whether the client requested it, and according to 609 * whether this is OPT_INFO or OPT_GO. */ 610 /* minimum - 1 for back-compat, or 512 if client is new enough. 611 * TODO: consult blk_bs(blk)->bl.request_alignment? */ 612 sizes[0] = 613 (client->opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1; 614 /* preferred - Hard-code to 4096 for now. 615 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 616 sizes[1] = 4096; 617 /* maximum - At most 32M, but smaller as appropriate. */ 618 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE); 619 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 620 sizes[0] = cpu_to_be32(sizes[0]); 621 sizes[1] = cpu_to_be32(sizes[1]); 622 sizes[2] = cpu_to_be32(sizes[2]); 623 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 624 sizeof(sizes), sizes, errp); 625 if (rc < 0) { 626 return rc; 627 } 628 629 /* Send NBD_INFO_EXPORT always */ 630 trace_nbd_negotiate_new_style_size_flags(exp->size, 631 exp->nbdflags | myflags); 632 stq_be_p(buf, exp->size); 633 stw_be_p(buf + 8, exp->nbdflags | myflags); 634 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 635 sizeof(buf), buf, errp); 636 if (rc < 0) { 637 return rc; 638 } 639 640 /* If the client is just asking for NBD_OPT_INFO, but forgot to 641 * request block sizes, return an error. 642 * TODO: consult blk_bs(blk)->request_align, and only error if it 643 * is not 1? */ 644 if (client->opt == NBD_OPT_INFO && !blocksize) { 645 return nbd_negotiate_send_rep_err(client, 646 NBD_REP_ERR_BLOCK_SIZE_REQD, 647 errp, 648 "request NBD_INFO_BLOCK_SIZE to " 649 "use this export"); 650 } 651 652 /* Final reply */ 653 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 654 if (rc < 0) { 655 return rc; 656 } 657 658 if (client->opt == NBD_OPT_GO) { 659 client->exp = exp; 660 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 661 nbd_export_get(client->exp); 662 nbd_check_meta_export(client); 663 rc = 1; 664 } 665 return rc; 666 } 667 668 669 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 670 * new channel for all further (now-encrypted) communication. */ 671 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 672 Error **errp) 673 { 674 QIOChannel *ioc; 675 QIOChannelTLS *tioc; 676 struct NBDTLSHandshakeData data = { 0 }; 677 678 assert(client->opt == NBD_OPT_STARTTLS); 679 680 trace_nbd_negotiate_handle_starttls(); 681 ioc = client->ioc; 682 683 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 684 return NULL; 685 } 686 687 tioc = qio_channel_tls_new_server(ioc, 688 client->tlscreds, 689 client->tlsauthz, 690 errp); 691 if (!tioc) { 692 return NULL; 693 } 694 695 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 696 trace_nbd_negotiate_handle_starttls_handshake(); 697 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 698 qio_channel_tls_handshake(tioc, 699 nbd_tls_handshake, 700 &data, 701 NULL, 702 NULL); 703 704 if (!data.complete) { 705 g_main_loop_run(data.loop); 706 } 707 g_main_loop_unref(data.loop); 708 if (data.error) { 709 object_unref(OBJECT(tioc)); 710 error_propagate(errp, data.error); 711 return NULL; 712 } 713 714 return QIO_CHANNEL(tioc); 715 } 716 717 /* nbd_negotiate_send_meta_context 718 * 719 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT 720 * 721 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead. 722 */ 723 static int nbd_negotiate_send_meta_context(NBDClient *client, 724 const char *context, 725 uint32_t context_id, 726 Error **errp) 727 { 728 NBDOptionReplyMetaContext opt; 729 struct iovec iov[] = { 730 {.iov_base = &opt, .iov_len = sizeof(opt)}, 731 {.iov_base = (void *)context, .iov_len = strlen(context)} 732 }; 733 734 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 735 context_id = 0; 736 } 737 738 trace_nbd_negotiate_meta_query_reply(context, context_id); 739 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT, 740 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len); 741 stl_be_p(&opt.context_id, context_id); 742 743 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; 744 } 745 746 /* Read strlen(@pattern) bytes, and set @match to true if they match @pattern. 747 * @match is never set to false. 748 * 749 * Return -errno on I/O error, 0 if option was completely handled by 750 * sending a reply about inconsistent lengths, or 1 on success. 751 * 752 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 753 * It only means that there are no errors. 754 */ 755 static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match, 756 Error **errp) 757 { 758 int ret; 759 char *query; 760 size_t len = strlen(pattern); 761 762 assert(len); 763 764 query = g_malloc(len); 765 ret = nbd_opt_read(client, query, len, errp); 766 if (ret <= 0) { 767 g_free(query); 768 return ret; 769 } 770 771 if (strncmp(query, pattern, len) == 0) { 772 trace_nbd_negotiate_meta_query_parse(pattern); 773 *match = true; 774 } else { 775 trace_nbd_negotiate_meta_query_skip("pattern not matched"); 776 } 777 g_free(query); 778 779 return 1; 780 } 781 782 /* 783 * Read @len bytes, and set @match to true if they match @pattern, or if @len 784 * is 0 and the client is performing _LIST_. @match is never set to false. 785 * 786 * Return -errno on I/O error, 0 if option was completely handled by 787 * sending a reply about inconsistent lengths, or 1 on success. 788 * 789 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 790 * It only means that there are no errors. 791 */ 792 static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, 793 uint32_t len, bool *match, Error **errp) 794 { 795 if (len == 0) { 796 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 797 *match = true; 798 } 799 trace_nbd_negotiate_meta_query_parse("empty"); 800 return 1; 801 } 802 803 if (len != strlen(pattern)) { 804 trace_nbd_negotiate_meta_query_skip("different lengths"); 805 return nbd_opt_skip(client, len, errp); 806 } 807 808 return nbd_meta_pattern(client, pattern, match, errp); 809 } 810 811 /* nbd_meta_base_query 812 * 813 * Handle queries to 'base' namespace. For now, only the base:allocation 814 * context is available. 'len' is the amount of text remaining to be read from 815 * the current name, after the 'base:' portion has been stripped. 816 * 817 * Return -errno on I/O error, 0 if option was completely handled by 818 * sending a reply about inconsistent lengths, or 1 on success. 819 */ 820 static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta, 821 uint32_t len, Error **errp) 822 { 823 return nbd_meta_empty_or_pattern(client, "allocation", len, 824 &meta->base_allocation, errp); 825 } 826 827 /* nbd_meta_bitmap_query 828 * 829 * Handle query to 'qemu:' namespace. 830 * @len is the amount of text remaining to be read from the current name, after 831 * the 'qemu:' portion has been stripped. 832 * 833 * Return -errno on I/O error, 0 if option was completely handled by 834 * sending a reply about inconsistent lengths, or 1 on success. */ 835 static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta, 836 uint32_t len, Error **errp) 837 { 838 bool dirty_bitmap = false; 839 size_t dirty_bitmap_len = strlen("dirty-bitmap:"); 840 int ret; 841 842 if (!meta->exp->export_bitmap) { 843 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported"); 844 return nbd_opt_skip(client, len, errp); 845 } 846 847 if (len == 0) { 848 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 849 meta->bitmap = true; 850 } 851 trace_nbd_negotiate_meta_query_parse("empty"); 852 return 1; 853 } 854 855 if (len < dirty_bitmap_len) { 856 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 857 return nbd_opt_skip(client, len, errp); 858 } 859 860 len -= dirty_bitmap_len; 861 ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp); 862 if (ret <= 0) { 863 return ret; 864 } 865 if (!dirty_bitmap) { 866 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 867 return nbd_opt_skip(client, len, errp); 868 } 869 870 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); 871 872 return nbd_meta_empty_or_pattern( 873 client, meta->exp->export_bitmap_context + 874 strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp); 875 } 876 877 /* nbd_negotiate_meta_query 878 * 879 * Parse namespace name and call corresponding function to parse body of the 880 * query. 881 * 882 * The only supported namespace now is 'base'. 883 * 884 * The function aims not wasting time and memory to read long unknown namespace 885 * names. 886 * 887 * Return -errno on I/O error, 0 if option was completely handled by 888 * sending a reply about inconsistent lengths, or 1 on success. */ 889 static int nbd_negotiate_meta_query(NBDClient *client, 890 NBDExportMetaContexts *meta, Error **errp) 891 { 892 /* 893 * Both 'qemu' and 'base' namespaces have length = 5 including a 894 * colon. If another length namespace is later introduced, this 895 * should certainly be refactored. 896 */ 897 int ret; 898 size_t ns_len = 5; 899 char ns[5]; 900 uint32_t len; 901 902 ret = nbd_opt_read(client, &len, sizeof(len), errp); 903 if (ret <= 0) { 904 return ret; 905 } 906 len = cpu_to_be32(len); 907 908 if (len < ns_len) { 909 trace_nbd_negotiate_meta_query_skip("length too short"); 910 return nbd_opt_skip(client, len, errp); 911 } 912 913 len -= ns_len; 914 ret = nbd_opt_read(client, ns, ns_len, errp); 915 if (ret <= 0) { 916 return ret; 917 } 918 919 if (!strncmp(ns, "base:", ns_len)) { 920 trace_nbd_negotiate_meta_query_parse("base:"); 921 return nbd_meta_base_query(client, meta, len, errp); 922 } else if (!strncmp(ns, "qemu:", ns_len)) { 923 trace_nbd_negotiate_meta_query_parse("qemu:"); 924 return nbd_meta_qemu_query(client, meta, len, errp); 925 } 926 927 trace_nbd_negotiate_meta_query_skip("unknown namespace"); 928 return nbd_opt_skip(client, len, errp); 929 } 930 931 /* nbd_negotiate_meta_queries 932 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT 933 * 934 * Return -errno on I/O error, or 0 if option was completely handled. */ 935 static int nbd_negotiate_meta_queries(NBDClient *client, 936 NBDExportMetaContexts *meta, Error **errp) 937 { 938 int ret; 939 char export_name[NBD_MAX_NAME_SIZE + 1]; 940 NBDExportMetaContexts local_meta; 941 uint32_t nb_queries; 942 int i; 943 944 if (!client->structured_reply) { 945 return nbd_opt_invalid(client, errp, 946 "request option '%s' when structured reply " 947 "is not negotiated", 948 nbd_opt_lookup(client->opt)); 949 } 950 951 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 952 /* Only change the caller's meta on SET. */ 953 meta = &local_meta; 954 } 955 956 memset(meta, 0, sizeof(*meta)); 957 958 ret = nbd_opt_read_name(client, export_name, NULL, errp); 959 if (ret <= 0) { 960 return ret; 961 } 962 963 meta->exp = nbd_export_find(export_name); 964 if (meta->exp == NULL) { 965 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, 966 "export '%s' not present", export_name); 967 } 968 969 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp); 970 if (ret <= 0) { 971 return ret; 972 } 973 nb_queries = cpu_to_be32(nb_queries); 974 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), 975 export_name, nb_queries); 976 977 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { 978 /* enable all known contexts */ 979 meta->base_allocation = true; 980 meta->bitmap = !!meta->exp->export_bitmap; 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_read32(client->ioc, &flags, "flags", errp) < 0) { 1049 return -EIO; 1050 } 1051 trace_nbd_negotiate_options_flags(flags); 1052 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1053 fixedNewstyle = true; 1054 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1055 } 1056 if (flags & NBD_FLAG_C_NO_ZEROES) { 1057 no_zeroes = true; 1058 flags &= ~NBD_FLAG_C_NO_ZEROES; 1059 } 1060 if (flags != 0) { 1061 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1062 return -EINVAL; 1063 } 1064 1065 while (1) { 1066 int ret; 1067 uint32_t option, length; 1068 uint64_t magic; 1069 1070 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) { 1071 return -EINVAL; 1072 } 1073 trace_nbd_negotiate_options_check_magic(magic); 1074 if (magic != NBD_OPTS_MAGIC) { 1075 error_setg(errp, "Bad magic received"); 1076 return -EINVAL; 1077 } 1078 1079 if (nbd_read32(client->ioc, &option, "option", errp) < 0) { 1080 return -EINVAL; 1081 } 1082 client->opt = option; 1083 1084 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) { 1085 return -EINVAL; 1086 } 1087 assert(!client->optlen); 1088 client->optlen = length; 1089 1090 if (length > NBD_MAX_BUFFER_SIZE) { 1091 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1092 length, NBD_MAX_BUFFER_SIZE); 1093 return -EINVAL; 1094 } 1095 1096 trace_nbd_negotiate_options_check_option(option, 1097 nbd_opt_lookup(option)); 1098 if (client->tlscreds && 1099 client->ioc == (QIOChannel *)client->sioc) { 1100 QIOChannel *tioc; 1101 if (!fixedNewstyle) { 1102 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1103 return -EINVAL; 1104 } 1105 switch (option) { 1106 case NBD_OPT_STARTTLS: 1107 if (length) { 1108 /* Unconditionally drop the connection if the client 1109 * can't start a TLS negotiation correctly */ 1110 return nbd_reject_length(client, true, errp); 1111 } 1112 tioc = nbd_negotiate_handle_starttls(client, errp); 1113 if (!tioc) { 1114 return -EIO; 1115 } 1116 ret = 0; 1117 object_unref(OBJECT(client->ioc)); 1118 client->ioc = QIO_CHANNEL(tioc); 1119 break; 1120 1121 case NBD_OPT_EXPORT_NAME: 1122 /* No way to return an error to client, so drop connection */ 1123 error_setg(errp, "Option 0x%x not permitted before TLS", 1124 option); 1125 return -EINVAL; 1126 1127 default: 1128 /* Let the client keep trying, unless they asked to 1129 * quit. Always try to give an error back to the 1130 * client; but when replying to OPT_ABORT, be aware 1131 * that the client may hang up before receiving the 1132 * error, in which case we are fine ignoring the 1133 * resulting EPIPE. */ 1134 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, 1135 option == NBD_OPT_ABORT ? NULL : errp, 1136 "Option 0x%" PRIx32 1137 " not permitted before TLS", option); 1138 if (option == NBD_OPT_ABORT) { 1139 return 1; 1140 } 1141 break; 1142 } 1143 } else if (fixedNewstyle) { 1144 switch (option) { 1145 case NBD_OPT_LIST: 1146 if (length) { 1147 ret = nbd_reject_length(client, false, errp); 1148 } else { 1149 ret = nbd_negotiate_handle_list(client, errp); 1150 } 1151 break; 1152 1153 case NBD_OPT_ABORT: 1154 /* NBD spec says we must try to reply before 1155 * disconnecting, but that we must also tolerate 1156 * guests that don't wait for our reply. */ 1157 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1158 return 1; 1159 1160 case NBD_OPT_EXPORT_NAME: 1161 return nbd_negotiate_handle_export_name(client, 1162 myflags, no_zeroes, 1163 errp); 1164 1165 case NBD_OPT_INFO: 1166 case NBD_OPT_GO: 1167 ret = nbd_negotiate_handle_info(client, myflags, errp); 1168 if (ret == 1) { 1169 assert(option == NBD_OPT_GO); 1170 return 0; 1171 } 1172 break; 1173 1174 case NBD_OPT_STARTTLS: 1175 if (length) { 1176 ret = nbd_reject_length(client, false, errp); 1177 } else if (client->tlscreds) { 1178 ret = nbd_negotiate_send_rep_err(client, 1179 NBD_REP_ERR_INVALID, errp, 1180 "TLS already enabled"); 1181 } else { 1182 ret = nbd_negotiate_send_rep_err(client, 1183 NBD_REP_ERR_POLICY, errp, 1184 "TLS not configured"); 1185 } 1186 break; 1187 1188 case NBD_OPT_STRUCTURED_REPLY: 1189 if (length) { 1190 ret = nbd_reject_length(client, false, errp); 1191 } else if (client->structured_reply) { 1192 ret = nbd_negotiate_send_rep_err( 1193 client, NBD_REP_ERR_INVALID, errp, 1194 "structured reply already negotiated"); 1195 } else { 1196 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1197 client->structured_reply = true; 1198 myflags |= NBD_FLAG_SEND_DF; 1199 } 1200 break; 1201 1202 case NBD_OPT_LIST_META_CONTEXT: 1203 case NBD_OPT_SET_META_CONTEXT: 1204 ret = nbd_negotiate_meta_queries(client, &client->export_meta, 1205 errp); 1206 break; 1207 1208 default: 1209 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1210 "Unsupported option %" PRIu32 " (%s)", 1211 option, nbd_opt_lookup(option)); 1212 break; 1213 } 1214 } else { 1215 /* 1216 * If broken new-style we should drop the connection 1217 * for anything except NBD_OPT_EXPORT_NAME 1218 */ 1219 switch (option) { 1220 case NBD_OPT_EXPORT_NAME: 1221 return nbd_negotiate_handle_export_name(client, 1222 myflags, no_zeroes, 1223 errp); 1224 1225 default: 1226 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1227 option, nbd_opt_lookup(option)); 1228 return -EINVAL; 1229 } 1230 } 1231 if (ret < 0) { 1232 return ret; 1233 } 1234 } 1235 } 1236 1237 /* nbd_negotiate 1238 * Return: 1239 * -errno on error, errp is set 1240 * 0 on successful negotiation, errp is not set 1241 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1242 * errp is not set 1243 */ 1244 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1245 { 1246 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1247 int ret; 1248 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | 1249 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA | 1250 NBD_FLAG_SEND_WRITE_ZEROES | NBD_FLAG_SEND_CACHE); 1251 1252 /* Old style negotiation header, no room for options 1253 [ 0 .. 7] passwd ("NBDMAGIC") 1254 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1255 [16 .. 23] size 1256 [24 .. 27] export flags (zero-extended) 1257 [28 .. 151] reserved (0) 1258 1259 New style negotiation header, client can send options 1260 [ 0 .. 7] passwd ("NBDMAGIC") 1261 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1262 [16 .. 17] server flags (0) 1263 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1264 */ 1265 1266 qio_channel_set_blocking(client->ioc, false, NULL); 1267 1268 trace_nbd_negotiate_begin(); 1269 memcpy(buf, "NBDMAGIC", 8); 1270 1271 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1272 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1273 1274 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 1275 error_prepend(errp, "write failed: "); 1276 return -EINVAL; 1277 } 1278 ret = nbd_negotiate_options(client, myflags, errp); 1279 if (ret != 0) { 1280 if (ret < 0) { 1281 error_prepend(errp, "option negotiation failed: "); 1282 } 1283 return ret; 1284 } 1285 1286 assert(!client->optlen); 1287 trace_nbd_negotiate_success(); 1288 1289 return 0; 1290 } 1291 1292 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 1293 Error **errp) 1294 { 1295 uint8_t buf[NBD_REQUEST_SIZE]; 1296 uint32_t magic; 1297 int ret; 1298 1299 ret = nbd_read(ioc, buf, sizeof(buf), "request", errp); 1300 if (ret < 0) { 1301 return ret; 1302 } 1303 1304 /* Request 1305 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1306 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1307 [ 6 .. 7] type (NBD_CMD_READ, ...) 1308 [ 8 .. 15] handle 1309 [16 .. 23] from 1310 [24 .. 27] len 1311 */ 1312 1313 magic = ldl_be_p(buf); 1314 request->flags = lduw_be_p(buf + 4); 1315 request->type = lduw_be_p(buf + 6); 1316 request->handle = ldq_be_p(buf + 8); 1317 request->from = ldq_be_p(buf + 16); 1318 request->len = ldl_be_p(buf + 24); 1319 1320 trace_nbd_receive_request(magic, request->flags, request->type, 1321 request->from, request->len); 1322 1323 if (magic != NBD_REQUEST_MAGIC) { 1324 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 1325 return -EINVAL; 1326 } 1327 return 0; 1328 } 1329 1330 #define MAX_NBD_REQUESTS 16 1331 1332 void nbd_client_get(NBDClient *client) 1333 { 1334 client->refcount++; 1335 } 1336 1337 void nbd_client_put(NBDClient *client) 1338 { 1339 if (--client->refcount == 0) { 1340 /* The last reference should be dropped by client->close, 1341 * which is called by client_close. 1342 */ 1343 assert(client->closing); 1344 1345 qio_channel_detach_aio_context(client->ioc); 1346 object_unref(OBJECT(client->sioc)); 1347 object_unref(OBJECT(client->ioc)); 1348 if (client->tlscreds) { 1349 object_unref(OBJECT(client->tlscreds)); 1350 } 1351 g_free(client->tlsauthz); 1352 if (client->exp) { 1353 QTAILQ_REMOVE(&client->exp->clients, client, next); 1354 nbd_export_put(client->exp); 1355 } 1356 g_free(client); 1357 } 1358 } 1359 1360 static void client_close(NBDClient *client, bool negotiated) 1361 { 1362 if (client->closing) { 1363 return; 1364 } 1365 1366 client->closing = true; 1367 1368 /* Force requests to finish. They will drop their own references, 1369 * then we'll close the socket and free the NBDClient. 1370 */ 1371 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1372 NULL); 1373 1374 /* Also tell the client, so that they release their reference. */ 1375 if (client->close_fn) { 1376 client->close_fn(client, negotiated); 1377 } 1378 } 1379 1380 static NBDRequestData *nbd_request_get(NBDClient *client) 1381 { 1382 NBDRequestData *req; 1383 1384 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1385 client->nb_requests++; 1386 1387 req = g_new0(NBDRequestData, 1); 1388 nbd_client_get(client); 1389 req->client = client; 1390 return req; 1391 } 1392 1393 static void nbd_request_put(NBDRequestData *req) 1394 { 1395 NBDClient *client = req->client; 1396 1397 if (req->data) { 1398 qemu_vfree(req->data); 1399 } 1400 g_free(req); 1401 1402 client->nb_requests--; 1403 nbd_client_receive_next_request(client); 1404 1405 nbd_client_put(client); 1406 } 1407 1408 static void blk_aio_attached(AioContext *ctx, void *opaque) 1409 { 1410 NBDExport *exp = opaque; 1411 NBDClient *client; 1412 1413 trace_nbd_blk_aio_attached(exp->name, ctx); 1414 1415 exp->ctx = ctx; 1416 1417 QTAILQ_FOREACH(client, &exp->clients, next) { 1418 qio_channel_attach_aio_context(client->ioc, ctx); 1419 if (client->recv_coroutine) { 1420 aio_co_schedule(ctx, client->recv_coroutine); 1421 } 1422 if (client->send_coroutine) { 1423 aio_co_schedule(ctx, client->send_coroutine); 1424 } 1425 } 1426 } 1427 1428 static void blk_aio_detach(void *opaque) 1429 { 1430 NBDExport *exp = opaque; 1431 NBDClient *client; 1432 1433 trace_nbd_blk_aio_detach(exp->name, exp->ctx); 1434 1435 QTAILQ_FOREACH(client, &exp->clients, next) { 1436 qio_channel_detach_aio_context(client->ioc); 1437 } 1438 1439 exp->ctx = NULL; 1440 } 1441 1442 static void nbd_eject_notifier(Notifier *n, void *data) 1443 { 1444 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1445 nbd_export_close(exp); 1446 } 1447 1448 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset, 1449 uint64_t size, const char *name, const char *desc, 1450 const char *bitmap, uint16_t nbdflags, 1451 void (*close)(NBDExport *), bool writethrough, 1452 BlockBackend *on_eject_blk, Error **errp) 1453 { 1454 AioContext *ctx; 1455 BlockBackend *blk; 1456 NBDExport *exp = g_new0(NBDExport, 1); 1457 uint64_t perm; 1458 int ret; 1459 1460 /* 1461 * NBD exports are used for non-shared storage migration. Make sure 1462 * that BDRV_O_INACTIVE is cleared and the image is ready for write 1463 * access since the export could be available before migration handover. 1464 */ 1465 assert(name); 1466 ctx = bdrv_get_aio_context(bs); 1467 aio_context_acquire(ctx); 1468 bdrv_invalidate_cache(bs, NULL); 1469 aio_context_release(ctx); 1470 1471 /* Don't allow resize while the NBD server is running, otherwise we don't 1472 * care what happens with the node. */ 1473 perm = BLK_PERM_CONSISTENT_READ; 1474 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) { 1475 perm |= BLK_PERM_WRITE; 1476 } 1477 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1478 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); 1479 ret = blk_insert_bs(blk, bs, errp); 1480 if (ret < 0) { 1481 goto fail; 1482 } 1483 blk_set_enable_write_cache(blk, !writethrough); 1484 1485 exp->refcount = 1; 1486 QTAILQ_INIT(&exp->clients); 1487 exp->blk = blk; 1488 assert(dev_offset <= INT64_MAX); 1489 exp->dev_offset = dev_offset; 1490 exp->name = g_strdup(name); 1491 exp->description = g_strdup(desc); 1492 exp->nbdflags = nbdflags; 1493 assert(size <= INT64_MAX - dev_offset); 1494 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); 1495 1496 if (bitmap) { 1497 BdrvDirtyBitmap *bm = NULL; 1498 1499 while (true) { 1500 bm = bdrv_find_dirty_bitmap(bs, bitmap); 1501 if (bm != NULL || bs->backing == NULL) { 1502 break; 1503 } 1504 1505 bs = bs->backing->bs; 1506 } 1507 1508 if (bm == NULL) { 1509 error_setg(errp, "Bitmap '%s' is not found", bitmap); 1510 goto fail; 1511 } 1512 1513 if ((nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) && 1514 bdrv_dirty_bitmap_enabled(bm)) { 1515 error_setg(errp, 1516 "Enabled bitmap '%s' incompatible with readonly export", 1517 bitmap); 1518 goto fail; 1519 } 1520 1521 if (bdrv_dirty_bitmap_user_locked(bm)) { 1522 error_setg(errp, "Bitmap '%s' is in use", bitmap); 1523 goto fail; 1524 } 1525 1526 bdrv_dirty_bitmap_set_qmp_locked(bm, true); 1527 exp->export_bitmap = bm; 1528 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s", 1529 bitmap); 1530 } 1531 1532 exp->close = close; 1533 exp->ctx = blk_get_aio_context(blk); 1534 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1535 1536 if (on_eject_blk) { 1537 blk_ref(on_eject_blk); 1538 exp->eject_notifier_blk = on_eject_blk; 1539 exp->eject_notifier.notify = nbd_eject_notifier; 1540 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier); 1541 } 1542 QTAILQ_INSERT_TAIL(&exports, exp, next); 1543 nbd_export_get(exp); 1544 return exp; 1545 1546 fail: 1547 blk_unref(blk); 1548 g_free(exp->name); 1549 g_free(exp->description); 1550 g_free(exp); 1551 return NULL; 1552 } 1553 1554 NBDExport *nbd_export_find(const char *name) 1555 { 1556 NBDExport *exp; 1557 QTAILQ_FOREACH(exp, &exports, next) { 1558 if (strcmp(name, exp->name) == 0) { 1559 return exp; 1560 } 1561 } 1562 1563 return NULL; 1564 } 1565 1566 void nbd_export_close(NBDExport *exp) 1567 { 1568 NBDClient *client, *next; 1569 1570 nbd_export_get(exp); 1571 /* 1572 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a 1573 * close mode that stops advertising the export to new clients but 1574 * still permits existing clients to run to completion? Because of 1575 * that possibility, nbd_export_close() can be called more than 1576 * once on an export. 1577 */ 1578 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1579 client_close(client, true); 1580 } 1581 if (exp->name) { 1582 nbd_export_put(exp); 1583 g_free(exp->name); 1584 exp->name = NULL; 1585 QTAILQ_REMOVE(&exports, exp, next); 1586 } 1587 g_free(exp->description); 1588 exp->description = NULL; 1589 nbd_export_put(exp); 1590 } 1591 1592 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp) 1593 { 1594 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) { 1595 nbd_export_close(exp); 1596 return; 1597 } 1598 1599 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE); 1600 1601 error_setg(errp, "export '%s' still in use", exp->name); 1602 error_append_hint(errp, "Use mode='hard' to force client disconnect\n"); 1603 } 1604 1605 void nbd_export_get(NBDExport *exp) 1606 { 1607 assert(exp->refcount > 0); 1608 exp->refcount++; 1609 } 1610 1611 void nbd_export_put(NBDExport *exp) 1612 { 1613 assert(exp->refcount > 0); 1614 if (exp->refcount == 1) { 1615 nbd_export_close(exp); 1616 } 1617 1618 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen 1619 * if someone calls nbd_export_put() on named export not through 1620 * nbd_export_set_name() when refcount is 1. So, let's assert that 1621 * it is > 0. 1622 */ 1623 assert(exp->refcount > 0); 1624 if (--exp->refcount == 0) { 1625 assert(exp->name == NULL); 1626 assert(exp->description == NULL); 1627 1628 if (exp->close) { 1629 exp->close(exp); 1630 } 1631 1632 if (exp->blk) { 1633 if (exp->eject_notifier_blk) { 1634 notifier_remove(&exp->eject_notifier); 1635 blk_unref(exp->eject_notifier_blk); 1636 } 1637 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, 1638 blk_aio_detach, exp); 1639 blk_unref(exp->blk); 1640 exp->blk = NULL; 1641 } 1642 1643 if (exp->export_bitmap) { 1644 bdrv_dirty_bitmap_set_qmp_locked(exp->export_bitmap, false); 1645 g_free(exp->export_bitmap_context); 1646 } 1647 1648 g_free(exp); 1649 } 1650 } 1651 1652 BlockBackend *nbd_export_get_blockdev(NBDExport *exp) 1653 { 1654 return exp->blk; 1655 } 1656 1657 void nbd_export_close_all(void) 1658 { 1659 NBDExport *exp, *next; 1660 1661 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { 1662 nbd_export_close(exp); 1663 } 1664 } 1665 1666 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1667 unsigned niov, Error **errp) 1668 { 1669 int ret; 1670 1671 g_assert(qemu_in_coroutine()); 1672 qemu_co_mutex_lock(&client->send_lock); 1673 client->send_coroutine = qemu_coroutine_self(); 1674 1675 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1676 1677 client->send_coroutine = NULL; 1678 qemu_co_mutex_unlock(&client->send_lock); 1679 1680 return ret; 1681 } 1682 1683 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1684 uint64_t handle) 1685 { 1686 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1687 stl_be_p(&reply->error, error); 1688 stq_be_p(&reply->handle, handle); 1689 } 1690 1691 static int nbd_co_send_simple_reply(NBDClient *client, 1692 uint64_t handle, 1693 uint32_t error, 1694 void *data, 1695 size_t len, 1696 Error **errp) 1697 { 1698 NBDSimpleReply reply; 1699 int nbd_err = system_errno_to_nbd_errno(error); 1700 struct iovec iov[] = { 1701 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1702 {.iov_base = data, .iov_len = len} 1703 }; 1704 1705 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1706 len); 1707 set_be_simple_reply(&reply, nbd_err, handle); 1708 1709 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1710 } 1711 1712 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1713 uint16_t type, uint64_t handle, uint32_t length) 1714 { 1715 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1716 stw_be_p(&chunk->flags, flags); 1717 stw_be_p(&chunk->type, type); 1718 stq_be_p(&chunk->handle, handle); 1719 stl_be_p(&chunk->length, length); 1720 } 1721 1722 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1723 uint64_t handle, 1724 Error **errp) 1725 { 1726 NBDStructuredReplyChunk chunk; 1727 struct iovec iov[] = { 1728 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1729 }; 1730 1731 trace_nbd_co_send_structured_done(handle); 1732 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1733 1734 return nbd_co_send_iov(client, iov, 1, errp); 1735 } 1736 1737 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1738 uint64_t handle, 1739 uint64_t offset, 1740 void *data, 1741 size_t size, 1742 bool final, 1743 Error **errp) 1744 { 1745 NBDStructuredReadData chunk; 1746 struct iovec iov[] = { 1747 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1748 {.iov_base = data, .iov_len = size} 1749 }; 1750 1751 assert(size); 1752 trace_nbd_co_send_structured_read(handle, offset, data, size); 1753 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1754 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1755 sizeof(chunk) - sizeof(chunk.h) + size); 1756 stq_be_p(&chunk.offset, offset); 1757 1758 return nbd_co_send_iov(client, iov, 2, errp); 1759 } 1760 1761 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1762 uint64_t handle, 1763 uint32_t error, 1764 const char *msg, 1765 Error **errp) 1766 { 1767 NBDStructuredError chunk; 1768 int nbd_err = system_errno_to_nbd_errno(error); 1769 struct iovec iov[] = { 1770 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1771 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1772 }; 1773 1774 assert(nbd_err); 1775 trace_nbd_co_send_structured_error(handle, nbd_err, 1776 nbd_err_lookup(nbd_err), msg ? msg : ""); 1777 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1778 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1779 stl_be_p(&chunk.error, nbd_err); 1780 stw_be_p(&chunk.message_length, iov[1].iov_len); 1781 1782 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1783 } 1784 1785 /* Do a sparse read and send the structured reply to the client. 1786 * Returns -errno if sending fails. bdrv_block_status_above() failure is 1787 * reported to the client, at which point this function succeeds. 1788 */ 1789 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1790 uint64_t handle, 1791 uint64_t offset, 1792 uint8_t *data, 1793 size_t size, 1794 Error **errp) 1795 { 1796 int ret = 0; 1797 NBDExport *exp = client->exp; 1798 size_t progress = 0; 1799 1800 while (progress < size) { 1801 int64_t pnum; 1802 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL, 1803 offset + progress, 1804 size - progress, &pnum, NULL, 1805 NULL); 1806 bool final; 1807 1808 if (status < 0) { 1809 char *msg = g_strdup_printf("unable to check for holes: %s", 1810 strerror(-status)); 1811 1812 ret = nbd_co_send_structured_error(client, handle, -status, msg, 1813 errp); 1814 g_free(msg); 1815 return ret; 1816 } 1817 assert(pnum && pnum <= size - progress); 1818 final = progress + pnum == size; 1819 if (status & BDRV_BLOCK_ZERO) { 1820 NBDStructuredReadHole chunk; 1821 struct iovec iov[] = { 1822 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1823 }; 1824 1825 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1826 pnum); 1827 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1828 NBD_REPLY_TYPE_OFFSET_HOLE, 1829 handle, sizeof(chunk) - sizeof(chunk.h)); 1830 stq_be_p(&chunk.offset, offset + progress); 1831 stl_be_p(&chunk.length, pnum); 1832 ret = nbd_co_send_iov(client, iov, 1, errp); 1833 } else { 1834 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset, 1835 data + progress, pnum); 1836 if (ret < 0) { 1837 error_setg_errno(errp, -ret, "reading from file failed"); 1838 break; 1839 } 1840 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1841 data + progress, pnum, final, 1842 errp); 1843 } 1844 1845 if (ret < 0) { 1846 break; 1847 } 1848 progress += pnum; 1849 } 1850 return ret; 1851 } 1852 1853 /* 1854 * Populate @extents from block status. Update @bytes to be the actual 1855 * length encoded (which may be smaller than the original), and update 1856 * @nb_extents to the number of extents used. 1857 * 1858 * Returns zero on success and -errno on bdrv_block_status_above failure. 1859 */ 1860 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, 1861 uint64_t *bytes, NBDExtent *extents, 1862 unsigned int *nb_extents) 1863 { 1864 uint64_t remaining_bytes = *bytes; 1865 NBDExtent *extent = extents, *extents_end = extents + *nb_extents; 1866 bool first_extent = true; 1867 1868 assert(*nb_extents); 1869 while (remaining_bytes) { 1870 uint32_t flags; 1871 int64_t num; 1872 int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes, 1873 &num, NULL, NULL); 1874 1875 if (ret < 0) { 1876 return ret; 1877 } 1878 1879 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) | 1880 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 1881 offset += num; 1882 remaining_bytes -= num; 1883 1884 if (first_extent) { 1885 extent->flags = flags; 1886 extent->length = num; 1887 first_extent = false; 1888 continue; 1889 } 1890 1891 if (flags == extent->flags) { 1892 /* extend current extent */ 1893 extent->length += num; 1894 } else { 1895 if (extent + 1 == extents_end) { 1896 break; 1897 } 1898 1899 /* start new extent */ 1900 extent++; 1901 extent->flags = flags; 1902 extent->length = num; 1903 } 1904 } 1905 1906 extents_end = extent + 1; 1907 1908 for (extent = extents; extent < extents_end; extent++) { 1909 extent->flags = cpu_to_be32(extent->flags); 1910 extent->length = cpu_to_be32(extent->length); 1911 } 1912 1913 *bytes -= remaining_bytes; 1914 *nb_extents = extents_end - extents; 1915 1916 return 0; 1917 } 1918 1919 /* nbd_co_send_extents 1920 * 1921 * @length is only for tracing purposes (and may be smaller or larger 1922 * than the client's original request). @last controls whether 1923 * NBD_REPLY_FLAG_DONE is sent. @extents should already be in 1924 * big-endian format. 1925 */ 1926 static int nbd_co_send_extents(NBDClient *client, uint64_t handle, 1927 NBDExtent *extents, unsigned int nb_extents, 1928 uint64_t length, bool last, 1929 uint32_t context_id, Error **errp) 1930 { 1931 NBDStructuredMeta chunk; 1932 1933 struct iovec iov[] = { 1934 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1935 {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])} 1936 }; 1937 1938 trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last); 1939 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0, 1940 NBD_REPLY_TYPE_BLOCK_STATUS, 1941 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1942 stl_be_p(&chunk.context_id, context_id); 1943 1944 return nbd_co_send_iov(client, iov, 2, errp); 1945 } 1946 1947 /* Get block status from the exported device and send it to the client */ 1948 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, 1949 BlockDriverState *bs, uint64_t offset, 1950 uint32_t length, bool dont_fragment, 1951 bool last, uint32_t context_id, 1952 Error **errp) 1953 { 1954 int ret; 1955 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; 1956 NBDExtent *extents = g_new(NBDExtent, nb_extents); 1957 uint64_t final_length = length; 1958 1959 ret = blockstatus_to_extents(bs, offset, &final_length, extents, 1960 &nb_extents); 1961 if (ret < 0) { 1962 g_free(extents); 1963 return nbd_co_send_structured_error( 1964 client, handle, -ret, "can't get block status", errp); 1965 } 1966 1967 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 1968 final_length, last, context_id, errp); 1969 1970 g_free(extents); 1971 1972 return ret; 1973 } 1974 1975 /* 1976 * Populate @extents from a dirty bitmap. Unless @dont_fragment, the 1977 * final extent may exceed the original @length. Store in @length the 1978 * byte length encoded (which may be smaller or larger than the 1979 * original), and return the number of extents used. 1980 */ 1981 static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset, 1982 uint64_t *length, NBDExtent *extents, 1983 unsigned int nb_extents, 1984 bool dont_fragment) 1985 { 1986 uint64_t begin = offset, end = offset; 1987 uint64_t overall_end = offset + *length; 1988 unsigned int i = 0; 1989 BdrvDirtyBitmapIter *it; 1990 bool dirty; 1991 1992 bdrv_dirty_bitmap_lock(bitmap); 1993 1994 it = bdrv_dirty_iter_new(bitmap); 1995 dirty = bdrv_get_dirty_locked(NULL, bitmap, offset); 1996 1997 assert(begin < overall_end && nb_extents); 1998 while (begin < overall_end && i < nb_extents) { 1999 bool next_dirty = !dirty; 2000 2001 if (dirty) { 2002 end = bdrv_dirty_bitmap_next_zero(bitmap, begin, UINT64_MAX); 2003 } else { 2004 bdrv_set_dirty_iter(it, begin); 2005 end = bdrv_dirty_iter_next(it); 2006 } 2007 if (end == -1 || end - begin > UINT32_MAX) { 2008 /* Cap to an aligned value < 4G beyond begin. */ 2009 end = MIN(bdrv_dirty_bitmap_size(bitmap), 2010 begin + UINT32_MAX + 1 - 2011 bdrv_dirty_bitmap_granularity(bitmap)); 2012 next_dirty = dirty; 2013 } 2014 if (dont_fragment && end > overall_end) { 2015 end = overall_end; 2016 } 2017 2018 extents[i].length = cpu_to_be32(end - begin); 2019 extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0); 2020 i++; 2021 begin = end; 2022 dirty = next_dirty; 2023 } 2024 2025 bdrv_dirty_iter_free(it); 2026 2027 bdrv_dirty_bitmap_unlock(bitmap); 2028 2029 assert(offset < end); 2030 *length = end - offset; 2031 return i; 2032 } 2033 2034 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, 2035 BdrvDirtyBitmap *bitmap, uint64_t offset, 2036 uint32_t length, bool dont_fragment, bool last, 2037 uint32_t context_id, Error **errp) 2038 { 2039 int ret; 2040 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; 2041 NBDExtent *extents = g_new(NBDExtent, nb_extents); 2042 uint64_t final_length = length; 2043 2044 nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents, 2045 nb_extents, dont_fragment); 2046 2047 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 2048 final_length, last, context_id, errp); 2049 2050 g_free(extents); 2051 2052 return ret; 2053 } 2054 2055 /* nbd_co_receive_request 2056 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2057 * connection right away, and any other negative value to report an error to 2058 * the client (although the caller may still need to disconnect after reporting 2059 * the error). 2060 */ 2061 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 2062 Error **errp) 2063 { 2064 NBDClient *client = req->client; 2065 int valid_flags; 2066 2067 g_assert(qemu_in_coroutine()); 2068 assert(client->recv_coroutine == qemu_coroutine_self()); 2069 if (nbd_receive_request(client->ioc, request, errp) < 0) { 2070 return -EIO; 2071 } 2072 2073 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 2074 nbd_cmd_lookup(request->type)); 2075 2076 if (request->type != NBD_CMD_WRITE) { 2077 /* No payload, we are ready to read the next request. */ 2078 req->complete = true; 2079 } 2080 2081 if (request->type == NBD_CMD_DISC) { 2082 /* Special case: we're going to disconnect without a reply, 2083 * whether or not flags, from, or len are bogus */ 2084 return -EIO; 2085 } 2086 2087 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE || 2088 request->type == NBD_CMD_CACHE) 2089 { 2090 if (request->len > NBD_MAX_BUFFER_SIZE) { 2091 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 2092 request->len, NBD_MAX_BUFFER_SIZE); 2093 return -EINVAL; 2094 } 2095 2096 req->data = blk_try_blockalign(client->exp->blk, request->len); 2097 if (req->data == NULL) { 2098 error_setg(errp, "No memory"); 2099 return -ENOMEM; 2100 } 2101 } 2102 if (request->type == NBD_CMD_WRITE) { 2103 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data", 2104 errp) < 0) 2105 { 2106 return -EIO; 2107 } 2108 req->complete = true; 2109 2110 trace_nbd_co_receive_request_payload_received(request->handle, 2111 request->len); 2112 } 2113 2114 /* Sanity checks. */ 2115 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 2116 (request->type == NBD_CMD_WRITE || 2117 request->type == NBD_CMD_WRITE_ZEROES || 2118 request->type == NBD_CMD_TRIM)) { 2119 error_setg(errp, "Export is read-only"); 2120 return -EROFS; 2121 } 2122 if (request->from > client->exp->size || 2123 request->len > client->exp->size - request->from) { 2124 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 2125 ", Size: %" PRIu64, request->from, request->len, 2126 client->exp->size); 2127 return (request->type == NBD_CMD_WRITE || 2128 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2129 } 2130 valid_flags = NBD_CMD_FLAG_FUA; 2131 if (request->type == NBD_CMD_READ && client->structured_reply) { 2132 valid_flags |= NBD_CMD_FLAG_DF; 2133 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 2134 valid_flags |= NBD_CMD_FLAG_NO_HOLE; 2135 } else if (request->type == NBD_CMD_BLOCK_STATUS) { 2136 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2137 } 2138 if (request->flags & ~valid_flags) { 2139 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2140 nbd_cmd_lookup(request->type), request->flags); 2141 return -EINVAL; 2142 } 2143 2144 return 0; 2145 } 2146 2147 /* Send simple reply without a payload, or a structured error 2148 * @error_msg is ignored if @ret >= 0 2149 * Returns 0 if connection is still live, -errno on failure to talk to client 2150 */ 2151 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2152 uint64_t handle, 2153 int ret, 2154 const char *error_msg, 2155 Error **errp) 2156 { 2157 if (client->structured_reply && ret < 0) { 2158 return nbd_co_send_structured_error(client, handle, -ret, error_msg, 2159 errp); 2160 } else { 2161 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0, 2162 NULL, 0, errp); 2163 } 2164 } 2165 2166 /* Handle NBD_CMD_READ request. 2167 * Return -errno if sending fails. Other errors are reported directly to the 2168 * client as an error reply. */ 2169 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2170 uint8_t *data, Error **errp) 2171 { 2172 int ret; 2173 NBDExport *exp = client->exp; 2174 2175 assert(request->type == NBD_CMD_READ || request->type == NBD_CMD_CACHE); 2176 2177 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2178 if (request->flags & NBD_CMD_FLAG_FUA) { 2179 ret = blk_co_flush(exp->blk); 2180 if (ret < 0) { 2181 return nbd_send_generic_reply(client, request->handle, ret, 2182 "flush failed", errp); 2183 } 2184 } 2185 2186 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) && 2187 request->len && request->type != NBD_CMD_CACHE) 2188 { 2189 return nbd_co_send_sparse_read(client, request->handle, request->from, 2190 data, request->len, errp); 2191 } 2192 2193 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data, 2194 request->len); 2195 if (ret < 0 || request->type == NBD_CMD_CACHE) { 2196 return nbd_send_generic_reply(client, request->handle, ret, 2197 "reading from file failed", errp); 2198 } 2199 2200 if (client->structured_reply) { 2201 if (request->len) { 2202 return nbd_co_send_structured_read(client, request->handle, 2203 request->from, data, 2204 request->len, true, errp); 2205 } else { 2206 return nbd_co_send_structured_done(client, request->handle, errp); 2207 } 2208 } else { 2209 return nbd_co_send_simple_reply(client, request->handle, 0, 2210 data, request->len, errp); 2211 } 2212 } 2213 2214 /* Handle NBD request. 2215 * Return -errno if sending fails. Other errors are reported directly to the 2216 * client as an error reply. */ 2217 static coroutine_fn int nbd_handle_request(NBDClient *client, 2218 NBDRequest *request, 2219 uint8_t *data, Error **errp) 2220 { 2221 int ret; 2222 int flags; 2223 NBDExport *exp = client->exp; 2224 char *msg; 2225 2226 switch (request->type) { 2227 case NBD_CMD_READ: 2228 case NBD_CMD_CACHE: 2229 return nbd_do_cmd_read(client, request, data, errp); 2230 2231 case NBD_CMD_WRITE: 2232 flags = 0; 2233 if (request->flags & NBD_CMD_FLAG_FUA) { 2234 flags |= BDRV_REQ_FUA; 2235 } 2236 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset, 2237 data, request->len, flags); 2238 return nbd_send_generic_reply(client, request->handle, ret, 2239 "writing to file failed", errp); 2240 2241 case NBD_CMD_WRITE_ZEROES: 2242 flags = 0; 2243 if (request->flags & NBD_CMD_FLAG_FUA) { 2244 flags |= BDRV_REQ_FUA; 2245 } 2246 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2247 flags |= BDRV_REQ_MAY_UNMAP; 2248 } 2249 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset, 2250 request->len, flags); 2251 return nbd_send_generic_reply(client, request->handle, ret, 2252 "writing to file failed", errp); 2253 2254 case NBD_CMD_DISC: 2255 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2256 abort(); 2257 2258 case NBD_CMD_FLUSH: 2259 ret = blk_co_flush(exp->blk); 2260 return nbd_send_generic_reply(client, request->handle, ret, 2261 "flush failed", errp); 2262 2263 case NBD_CMD_TRIM: 2264 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset, 2265 request->len); 2266 if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) { 2267 ret = blk_co_flush(exp->blk); 2268 } 2269 return nbd_send_generic_reply(client, request->handle, ret, 2270 "discard failed", errp); 2271 2272 case NBD_CMD_BLOCK_STATUS: 2273 if (!request->len) { 2274 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2275 "need non-zero length", errp); 2276 } 2277 if (client->export_meta.valid && 2278 (client->export_meta.base_allocation || 2279 client->export_meta.bitmap)) 2280 { 2281 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2282 2283 if (client->export_meta.base_allocation) { 2284 ret = nbd_co_send_block_status(client, request->handle, 2285 blk_bs(exp->blk), request->from, 2286 request->len, dont_fragment, 2287 !client->export_meta.bitmap, 2288 NBD_META_ID_BASE_ALLOCATION, 2289 errp); 2290 if (ret < 0) { 2291 return ret; 2292 } 2293 } 2294 2295 if (client->export_meta.bitmap) { 2296 ret = nbd_co_send_bitmap(client, request->handle, 2297 client->exp->export_bitmap, 2298 request->from, request->len, 2299 dont_fragment, 2300 true, NBD_META_ID_DIRTY_BITMAP, errp); 2301 if (ret < 0) { 2302 return ret; 2303 } 2304 } 2305 2306 return ret; 2307 } else { 2308 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2309 "CMD_BLOCK_STATUS not negotiated", 2310 errp); 2311 } 2312 2313 default: 2314 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 2315 request->type); 2316 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg, 2317 errp); 2318 g_free(msg); 2319 return ret; 2320 } 2321 } 2322 2323 /* Owns a reference to the NBDClient passed as opaque. */ 2324 static coroutine_fn void nbd_trip(void *opaque) 2325 { 2326 NBDClient *client = opaque; 2327 NBDRequestData *req; 2328 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 2329 int ret; 2330 Error *local_err = NULL; 2331 2332 trace_nbd_trip(); 2333 if (client->closing) { 2334 nbd_client_put(client); 2335 return; 2336 } 2337 2338 req = nbd_request_get(client); 2339 ret = nbd_co_receive_request(req, &request, &local_err); 2340 client->recv_coroutine = NULL; 2341 2342 if (client->closing) { 2343 /* 2344 * The client may be closed when we are blocked in 2345 * nbd_co_receive_request() 2346 */ 2347 goto done; 2348 } 2349 2350 nbd_client_receive_next_request(client); 2351 if (ret == -EIO) { 2352 goto disconnect; 2353 } 2354 2355 if (ret < 0) { 2356 /* It wans't -EIO, so, according to nbd_co_receive_request() 2357 * semantics, we should return the error to the client. */ 2358 Error *export_err = local_err; 2359 2360 local_err = NULL; 2361 ret = nbd_send_generic_reply(client, request.handle, -EINVAL, 2362 error_get_pretty(export_err), &local_err); 2363 error_free(export_err); 2364 } else { 2365 ret = nbd_handle_request(client, &request, req->data, &local_err); 2366 } 2367 if (ret < 0) { 2368 error_prepend(&local_err, "Failed to send reply: "); 2369 goto disconnect; 2370 } 2371 2372 /* We must disconnect after NBD_CMD_WRITE if we did not 2373 * read the payload. 2374 */ 2375 if (!req->complete) { 2376 error_setg(&local_err, "Request handling failed in intermediate state"); 2377 goto disconnect; 2378 } 2379 2380 done: 2381 nbd_request_put(req); 2382 nbd_client_put(client); 2383 return; 2384 2385 disconnect: 2386 if (local_err) { 2387 error_reportf_err(local_err, "Disconnect client, due to: "); 2388 } 2389 nbd_request_put(req); 2390 client_close(client, true); 2391 nbd_client_put(client); 2392 } 2393 2394 static void nbd_client_receive_next_request(NBDClient *client) 2395 { 2396 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 2397 nbd_client_get(client); 2398 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 2399 aio_co_schedule(client->exp->ctx, client->recv_coroutine); 2400 } 2401 } 2402 2403 static coroutine_fn void nbd_co_client_start(void *opaque) 2404 { 2405 NBDClient *client = opaque; 2406 Error *local_err = NULL; 2407 2408 qemu_co_mutex_init(&client->send_lock); 2409 2410 if (nbd_negotiate(client, &local_err)) { 2411 if (local_err) { 2412 error_report_err(local_err); 2413 } 2414 client_close(client, false); 2415 return; 2416 } 2417 2418 nbd_client_receive_next_request(client); 2419 } 2420 2421 /* 2422 * Create a new client listener using the given channel @sioc. 2423 * Begin servicing it in a coroutine. When the connection closes, call 2424 * @close_fn with an indication of whether the client completed negotiation. 2425 */ 2426 void nbd_client_new(QIOChannelSocket *sioc, 2427 QCryptoTLSCreds *tlscreds, 2428 const char *tlsauthz, 2429 void (*close_fn)(NBDClient *, bool)) 2430 { 2431 NBDClient *client; 2432 Coroutine *co; 2433 2434 client = g_new0(NBDClient, 1); 2435 client->refcount = 1; 2436 client->tlscreds = tlscreds; 2437 if (tlscreds) { 2438 object_ref(OBJECT(client->tlscreds)); 2439 } 2440 client->tlsauthz = g_strdup(tlsauthz); 2441 client->sioc = sioc; 2442 object_ref(OBJECT(client->sioc)); 2443 client->ioc = QIO_CHANNEL(sioc); 2444 object_ref(OBJECT(client->ioc)); 2445 client->close_fn = close_fn; 2446 2447 co = qemu_coroutine_create(nbd_co_client_start, client); 2448 qemu_coroutine_enter(co); 2449 } 2450