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 #include "qemu/units.h" 25 26 #define NBD_META_ID_BASE_ALLOCATION 0 27 #define NBD_META_ID_DIRTY_BITMAP 1 28 29 /* 30 * NBD_MAX_BLOCK_STATUS_EXTENTS: 1 MiB of extents data. An empirical 31 * constant. If an increase is needed, note that the NBD protocol 32 * recommends no larger than 32 mb, so that the client won't consider 33 * the reply as a denial of service attack. 34 */ 35 #define NBD_MAX_BLOCK_STATUS_EXTENTS (1 * MiB / 8) 36 37 static int system_errno_to_nbd_errno(int err) 38 { 39 switch (err) { 40 case 0: 41 return NBD_SUCCESS; 42 case EPERM: 43 case EROFS: 44 return NBD_EPERM; 45 case EIO: 46 return NBD_EIO; 47 case ENOMEM: 48 return NBD_ENOMEM; 49 #ifdef EDQUOT 50 case EDQUOT: 51 #endif 52 case EFBIG: 53 case ENOSPC: 54 return NBD_ENOSPC; 55 case EOVERFLOW: 56 return NBD_EOVERFLOW; 57 case ESHUTDOWN: 58 return NBD_ESHUTDOWN; 59 case EINVAL: 60 default: 61 return NBD_EINVAL; 62 } 63 } 64 65 /* Definitions for opaque data types */ 66 67 typedef struct NBDRequestData NBDRequestData; 68 69 struct NBDRequestData { 70 QSIMPLEQ_ENTRY(NBDRequestData) entry; 71 NBDClient *client; 72 uint8_t *data; 73 bool complete; 74 }; 75 76 struct NBDExport { 77 int refcount; 78 void (*close)(NBDExport *exp); 79 80 BlockBackend *blk; 81 char *name; 82 char *description; 83 uint64_t dev_offset; 84 uint64_t size; 85 uint16_t nbdflags; 86 QTAILQ_HEAD(, NBDClient) clients; 87 QTAILQ_ENTRY(NBDExport) next; 88 89 AioContext *ctx; 90 91 BlockBackend *eject_notifier_blk; 92 Notifier eject_notifier; 93 94 BdrvDirtyBitmap *export_bitmap; 95 char *export_bitmap_context; 96 }; 97 98 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); 99 100 /* NBDExportMetaContexts represents a list of contexts to be exported, 101 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for 102 * NBD_OPT_LIST_META_CONTEXT. */ 103 typedef struct NBDExportMetaContexts { 104 NBDExport *exp; 105 bool valid; /* means that negotiation of the option finished without 106 errors */ 107 bool base_allocation; /* export base:allocation context (block status) */ 108 bool bitmap; /* export qemu:dirty-bitmap:<export bitmap name> */ 109 } NBDExportMetaContexts; 110 111 struct NBDClient { 112 int refcount; 113 void (*close_fn)(NBDClient *client, bool negotiated); 114 115 NBDExport *exp; 116 QCryptoTLSCreds *tlscreds; 117 char *tlsauthz; 118 QIOChannelSocket *sioc; /* The underlying data channel */ 119 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ 120 121 Coroutine *recv_coroutine; 122 123 CoMutex send_lock; 124 Coroutine *send_coroutine; 125 126 QTAILQ_ENTRY(NBDClient) next; 127 int nb_requests; 128 bool closing; 129 130 uint32_t check_align; /* If non-zero, check for aligned client requests */ 131 132 bool structured_reply; 133 NBDExportMetaContexts export_meta; 134 135 uint32_t opt; /* Current option being negotiated */ 136 uint32_t optlen; /* remaining length of data in ioc for the option being 137 negotiated now */ 138 }; 139 140 static void nbd_client_receive_next_request(NBDClient *client); 141 142 /* Basic flow for negotiation 143 144 Server Client 145 Negotiate 146 147 or 148 149 Server Client 150 Negotiate #1 151 Option 152 Negotiate #2 153 154 ---- 155 156 followed by 157 158 Server Client 159 Request 160 Response 161 Request 162 Response 163 ... 164 ... 165 Request (type == 2) 166 167 */ 168 169 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option, 170 uint32_t type, uint32_t length) 171 { 172 stq_be_p(&rep->magic, NBD_REP_MAGIC); 173 stl_be_p(&rep->option, option); 174 stl_be_p(&rep->type, type); 175 stl_be_p(&rep->length, length); 176 } 177 178 /* Send a reply header, including length, but no payload. 179 * Return -errno on error, 0 on success. */ 180 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type, 181 uint32_t len, Error **errp) 182 { 183 NBDOptionReply rep; 184 185 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt), 186 type, nbd_rep_lookup(type), len); 187 188 assert(len < NBD_MAX_BUFFER_SIZE); 189 190 set_be_option_rep(&rep, client->opt, type, len); 191 return nbd_write(client->ioc, &rep, sizeof(rep), errp); 192 } 193 194 /* Send a reply header with default 0 length. 195 * Return -errno on error, 0 on success. */ 196 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type, 197 Error **errp) 198 { 199 return nbd_negotiate_send_rep_len(client, type, 0, errp); 200 } 201 202 /* Send an error reply. 203 * Return -errno on error, 0 on success. */ 204 static int GCC_FMT_ATTR(4, 0) 205 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, 206 Error **errp, const char *fmt, va_list va) 207 { 208 char *msg; 209 int ret; 210 size_t len; 211 212 msg = g_strdup_vprintf(fmt, va); 213 len = strlen(msg); 214 assert(len < 4096); 215 trace_nbd_negotiate_send_rep_err(msg); 216 ret = nbd_negotiate_send_rep_len(client, type, len, errp); 217 if (ret < 0) { 218 goto out; 219 } 220 if (nbd_write(client->ioc, msg, len, errp) < 0) { 221 error_prepend(errp, "write failed (error message): "); 222 ret = -EIO; 223 } else { 224 ret = 0; 225 } 226 227 out: 228 g_free(msg); 229 return ret; 230 } 231 232 /* Send an error reply. 233 * Return -errno on error, 0 on success. */ 234 static int GCC_FMT_ATTR(4, 5) 235 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type, 236 Error **errp, const char *fmt, ...) 237 { 238 va_list va; 239 int ret; 240 241 va_start(va, fmt); 242 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 243 va_end(va); 244 return ret; 245 } 246 247 /* Drop remainder of the current option, and send a reply with the 248 * given error type and message. Return -errno on read or write 249 * failure; or 0 if connection is still live. */ 250 static int GCC_FMT_ATTR(4, 0) 251 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp, 252 const char *fmt, va_list va) 253 { 254 int ret = nbd_drop(client->ioc, client->optlen, errp); 255 256 client->optlen = 0; 257 if (!ret) { 258 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 259 } 260 return ret; 261 } 262 263 static int GCC_FMT_ATTR(4, 5) 264 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp, 265 const char *fmt, ...) 266 { 267 int ret; 268 va_list va; 269 270 va_start(va, fmt); 271 ret = nbd_opt_vdrop(client, type, errp, fmt, va); 272 va_end(va); 273 274 return ret; 275 } 276 277 static int GCC_FMT_ATTR(3, 4) 278 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...) 279 { 280 int ret; 281 va_list va; 282 283 va_start(va, fmt); 284 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va); 285 va_end(va); 286 287 return ret; 288 } 289 290 /* Read size bytes from the unparsed payload of the current option. 291 * Return -errno on I/O error, 0 if option was completely handled by 292 * sending a reply about inconsistent lengths, or 1 on success. */ 293 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size, 294 Error **errp) 295 { 296 if (size > client->optlen) { 297 return nbd_opt_invalid(client, errp, 298 "Inconsistent lengths in option %s", 299 nbd_opt_lookup(client->opt)); 300 } 301 client->optlen -= size; 302 return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1; 303 } 304 305 /* Drop size bytes from the unparsed payload of the current option. 306 * Return -errno on I/O error, 0 if option was completely handled by 307 * sending a reply about inconsistent lengths, or 1 on success. */ 308 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp) 309 { 310 if (size > client->optlen) { 311 return nbd_opt_invalid(client, errp, 312 "Inconsistent lengths in option %s", 313 nbd_opt_lookup(client->opt)); 314 } 315 client->optlen -= size; 316 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1; 317 } 318 319 /* nbd_opt_read_name 320 * 321 * Read a string with the format: 322 * uint32_t len (<= NBD_MAX_NAME_SIZE) 323 * len bytes string (not 0-terminated) 324 * 325 * @name should be enough to store NBD_MAX_NAME_SIZE+1. 326 * If @length is non-null, it will be set to the actual string length. 327 * 328 * Return -errno on I/O error, 0 if option was completely handled by 329 * sending a reply about inconsistent lengths, or 1 on success. 330 */ 331 static int nbd_opt_read_name(NBDClient *client, char *name, uint32_t *length, 332 Error **errp) 333 { 334 int ret; 335 uint32_t len; 336 337 ret = nbd_opt_read(client, &len, sizeof(len), errp); 338 if (ret <= 0) { 339 return ret; 340 } 341 len = cpu_to_be32(len); 342 343 if (len > NBD_MAX_NAME_SIZE) { 344 return nbd_opt_invalid(client, errp, 345 "Invalid name length: %" PRIu32, len); 346 } 347 348 ret = nbd_opt_read(client, name, len, errp); 349 if (ret <= 0) { 350 return ret; 351 } 352 name[len] = '\0'; 353 354 if (length) { 355 *length = len; 356 } 357 358 return 1; 359 } 360 361 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 362 * Return -errno on error, 0 on success. */ 363 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, 364 Error **errp) 365 { 366 size_t name_len, desc_len; 367 uint32_t len; 368 const char *name = exp->name ? exp->name : ""; 369 const char *desc = exp->description ? exp->description : ""; 370 QIOChannel *ioc = client->ioc; 371 int ret; 372 373 trace_nbd_negotiate_send_rep_list(name, desc); 374 name_len = strlen(name); 375 desc_len = strlen(desc); 376 len = name_len + desc_len + sizeof(len); 377 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp); 378 if (ret < 0) { 379 return ret; 380 } 381 382 len = cpu_to_be32(name_len); 383 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 384 error_prepend(errp, "write failed (name length): "); 385 return -EINVAL; 386 } 387 388 if (nbd_write(ioc, name, name_len, errp) < 0) { 389 error_prepend(errp, "write failed (name buffer): "); 390 return -EINVAL; 391 } 392 393 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 394 error_prepend(errp, "write failed (description buffer): "); 395 return -EINVAL; 396 } 397 398 return 0; 399 } 400 401 /* Process the NBD_OPT_LIST command, with a potential series of replies. 402 * Return -errno on error, 0 on success. */ 403 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) 404 { 405 NBDExport *exp; 406 assert(client->opt == NBD_OPT_LIST); 407 408 /* For each export, send a NBD_REP_SERVER reply. */ 409 QTAILQ_FOREACH(exp, &exports, next) { 410 if (nbd_negotiate_send_rep_list(client, exp, errp)) { 411 return -EINVAL; 412 } 413 } 414 /* Finish with a NBD_REP_ACK. */ 415 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 416 } 417 418 static void nbd_check_meta_export(NBDClient *client) 419 { 420 client->export_meta.valid &= client->exp == client->export_meta.exp; 421 } 422 423 /* Send a reply to NBD_OPT_EXPORT_NAME. 424 * Return -errno on error, 0 on success. */ 425 static int nbd_negotiate_handle_export_name(NBDClient *client, 426 uint16_t myflags, bool no_zeroes, 427 Error **errp) 428 { 429 char name[NBD_MAX_NAME_SIZE + 1]; 430 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 431 size_t len; 432 int ret; 433 434 /* Client sends: 435 [20 .. xx] export name (length bytes) 436 Server replies: 437 [ 0 .. 7] size 438 [ 8 .. 9] export flags 439 [10 .. 133] reserved (0) [unless no_zeroes] 440 */ 441 trace_nbd_negotiate_handle_export_name(); 442 if (client->optlen >= sizeof(name)) { 443 error_setg(errp, "Bad length received"); 444 return -EINVAL; 445 } 446 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) { 447 return -EIO; 448 } 449 name[client->optlen] = '\0'; 450 client->optlen = 0; 451 452 trace_nbd_negotiate_handle_export_name_request(name); 453 454 client->exp = nbd_export_find(name); 455 if (!client->exp) { 456 error_setg(errp, "export not found"); 457 return -EINVAL; 458 } 459 460 trace_nbd_negotiate_new_style_size_flags(client->exp->size, 461 client->exp->nbdflags | myflags); 462 stq_be_p(buf, client->exp->size); 463 stw_be_p(buf + 8, client->exp->nbdflags | myflags); 464 len = no_zeroes ? 10 : sizeof(buf); 465 ret = nbd_write(client->ioc, buf, len, errp); 466 if (ret < 0) { 467 error_prepend(errp, "write failed: "); 468 return ret; 469 } 470 471 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 472 nbd_export_get(client->exp); 473 nbd_check_meta_export(client); 474 475 return 0; 476 } 477 478 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 479 * The buffer does NOT include the info type prefix. 480 * Return -errno on error, 0 if ready to send more. */ 481 static int nbd_negotiate_send_info(NBDClient *client, 482 uint16_t info, uint32_t length, void *buf, 483 Error **errp) 484 { 485 int rc; 486 487 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 488 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 489 sizeof(info) + length, errp); 490 if (rc < 0) { 491 return rc; 492 } 493 info = cpu_to_be16(info); 494 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 495 return -EIO; 496 } 497 if (nbd_write(client->ioc, buf, length, errp) < 0) { 498 return -EIO; 499 } 500 return 0; 501 } 502 503 /* nbd_reject_length: Handle any unexpected payload. 504 * @fatal requests that we quit talking to the client, even if we are able 505 * to successfully send an error reply. 506 * Return: 507 * -errno transmission error occurred or @fatal was requested, errp is set 508 * 0 error message successfully sent to client, errp is not set 509 */ 510 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 511 { 512 int ret; 513 514 assert(client->optlen); 515 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length", 516 nbd_opt_lookup(client->opt)); 517 if (fatal && !ret) { 518 error_setg(errp, "option '%s' has unexpected length", 519 nbd_opt_lookup(client->opt)); 520 return -EINVAL; 521 } 522 return ret; 523 } 524 525 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 526 * Return -errno on error, 0 if ready for next option, and 1 to move 527 * into transmission phase. */ 528 static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags, 529 Error **errp) 530 { 531 int rc; 532 char name[NBD_MAX_NAME_SIZE + 1]; 533 NBDExport *exp; 534 uint16_t requests; 535 uint16_t request; 536 uint32_t namelen; 537 bool sendname = false; 538 bool blocksize = false; 539 uint32_t sizes[3]; 540 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 541 uint32_t check_align = 0; 542 543 /* Client sends: 544 4 bytes: L, name length (can be 0) 545 L bytes: export name 546 2 bytes: N, number of requests (can be 0) 547 N * 2 bytes: N requests 548 */ 549 rc = nbd_opt_read_name(client, name, &namelen, errp); 550 if (rc <= 0) { 551 return rc; 552 } 553 trace_nbd_negotiate_handle_export_name_request(name); 554 555 rc = nbd_opt_read(client, &requests, sizeof(requests), errp); 556 if (rc <= 0) { 557 return rc; 558 } 559 requests = be16_to_cpu(requests); 560 trace_nbd_negotiate_handle_info_requests(requests); 561 while (requests--) { 562 rc = nbd_opt_read(client, &request, sizeof(request), errp); 563 if (rc <= 0) { 564 return rc; 565 } 566 request = be16_to_cpu(request); 567 trace_nbd_negotiate_handle_info_request(request, 568 nbd_info_lookup(request)); 569 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 570 * everything else is either a request we don't know or 571 * something we send regardless of request */ 572 switch (request) { 573 case NBD_INFO_NAME: 574 sendname = true; 575 break; 576 case NBD_INFO_BLOCK_SIZE: 577 blocksize = true; 578 break; 579 } 580 } 581 if (client->optlen) { 582 return nbd_reject_length(client, false, errp); 583 } 584 585 exp = nbd_export_find(name); 586 if (!exp) { 587 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 588 errp, "export '%s' not present", 589 name); 590 } 591 592 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 593 if (sendname) { 594 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 595 errp); 596 if (rc < 0) { 597 return rc; 598 } 599 } 600 601 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 602 * client request */ 603 if (exp->description) { 604 size_t len = strlen(exp->description); 605 606 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 607 len, exp->description, errp); 608 if (rc < 0) { 609 return rc; 610 } 611 } 612 613 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 614 * according to whether the client requested it, and according to 615 * whether this is OPT_INFO or OPT_GO. */ 616 /* minimum - 1 for back-compat, or actual if client will obey it. */ 617 if (client->opt == NBD_OPT_INFO || blocksize) { 618 check_align = sizes[0] = blk_get_request_alignment(exp->blk); 619 } else { 620 sizes[0] = 1; 621 } 622 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE); 623 /* preferred - Hard-code to 4096 for now. 624 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 625 sizes[1] = MAX(4096, sizes[0]); 626 /* maximum - At most 32M, but smaller as appropriate. */ 627 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE); 628 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 629 sizes[0] = cpu_to_be32(sizes[0]); 630 sizes[1] = cpu_to_be32(sizes[1]); 631 sizes[2] = cpu_to_be32(sizes[2]); 632 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 633 sizeof(sizes), sizes, errp); 634 if (rc < 0) { 635 return rc; 636 } 637 638 /* Send NBD_INFO_EXPORT always */ 639 trace_nbd_negotiate_new_style_size_flags(exp->size, 640 exp->nbdflags | myflags); 641 stq_be_p(buf, exp->size); 642 stw_be_p(buf + 8, exp->nbdflags | myflags); 643 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 644 sizeof(buf), buf, errp); 645 if (rc < 0) { 646 return rc; 647 } 648 649 /* 650 * If the client is just asking for NBD_OPT_INFO, but forgot to 651 * request block sizes in a situation that would impact 652 * performance, then return an error. But for NBD_OPT_GO, we 653 * tolerate all clients, regardless of alignments. 654 */ 655 if (client->opt == NBD_OPT_INFO && !blocksize && 656 blk_get_request_alignment(exp->blk) > 1) { 657 return nbd_negotiate_send_rep_err(client, 658 NBD_REP_ERR_BLOCK_SIZE_REQD, 659 errp, 660 "request NBD_INFO_BLOCK_SIZE to " 661 "use this export"); 662 } 663 664 /* Final reply */ 665 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 666 if (rc < 0) { 667 return rc; 668 } 669 670 if (client->opt == NBD_OPT_GO) { 671 client->exp = exp; 672 client->check_align = check_align; 673 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 674 nbd_export_get(client->exp); 675 nbd_check_meta_export(client); 676 rc = 1; 677 } 678 return rc; 679 } 680 681 682 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 683 * new channel for all further (now-encrypted) communication. */ 684 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 685 Error **errp) 686 { 687 QIOChannel *ioc; 688 QIOChannelTLS *tioc; 689 struct NBDTLSHandshakeData data = { 0 }; 690 691 assert(client->opt == NBD_OPT_STARTTLS); 692 693 trace_nbd_negotiate_handle_starttls(); 694 ioc = client->ioc; 695 696 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 697 return NULL; 698 } 699 700 tioc = qio_channel_tls_new_server(ioc, 701 client->tlscreds, 702 client->tlsauthz, 703 errp); 704 if (!tioc) { 705 return NULL; 706 } 707 708 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 709 trace_nbd_negotiate_handle_starttls_handshake(); 710 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 711 qio_channel_tls_handshake(tioc, 712 nbd_tls_handshake, 713 &data, 714 NULL, 715 NULL); 716 717 if (!data.complete) { 718 g_main_loop_run(data.loop); 719 } 720 g_main_loop_unref(data.loop); 721 if (data.error) { 722 object_unref(OBJECT(tioc)); 723 error_propagate(errp, data.error); 724 return NULL; 725 } 726 727 return QIO_CHANNEL(tioc); 728 } 729 730 /* nbd_negotiate_send_meta_context 731 * 732 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT 733 * 734 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead. 735 */ 736 static int nbd_negotiate_send_meta_context(NBDClient *client, 737 const char *context, 738 uint32_t context_id, 739 Error **errp) 740 { 741 NBDOptionReplyMetaContext opt; 742 struct iovec iov[] = { 743 {.iov_base = &opt, .iov_len = sizeof(opt)}, 744 {.iov_base = (void *)context, .iov_len = strlen(context)} 745 }; 746 747 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 748 context_id = 0; 749 } 750 751 trace_nbd_negotiate_meta_query_reply(context, context_id); 752 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT, 753 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len); 754 stl_be_p(&opt.context_id, context_id); 755 756 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; 757 } 758 759 /* Read strlen(@pattern) bytes, and set @match to true if they match @pattern. 760 * @match is never set to false. 761 * 762 * Return -errno on I/O error, 0 if option was completely handled by 763 * sending a reply about inconsistent lengths, or 1 on success. 764 * 765 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 766 * It only means that there are no errors. 767 */ 768 static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match, 769 Error **errp) 770 { 771 int ret; 772 char *query; 773 size_t len = strlen(pattern); 774 775 assert(len); 776 777 query = g_malloc(len); 778 ret = nbd_opt_read(client, query, len, errp); 779 if (ret <= 0) { 780 g_free(query); 781 return ret; 782 } 783 784 if (strncmp(query, pattern, len) == 0) { 785 trace_nbd_negotiate_meta_query_parse(pattern); 786 *match = true; 787 } else { 788 trace_nbd_negotiate_meta_query_skip("pattern not matched"); 789 } 790 g_free(query); 791 792 return 1; 793 } 794 795 /* 796 * Read @len bytes, and set @match to true if they match @pattern, or if @len 797 * is 0 and the client is performing _LIST_. @match is never set to false. 798 * 799 * Return -errno on I/O error, 0 if option was completely handled by 800 * sending a reply about inconsistent lengths, or 1 on success. 801 * 802 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 803 * It only means that there are no errors. 804 */ 805 static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, 806 uint32_t len, bool *match, Error **errp) 807 { 808 if (len == 0) { 809 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 810 *match = true; 811 } 812 trace_nbd_negotiate_meta_query_parse("empty"); 813 return 1; 814 } 815 816 if (len != strlen(pattern)) { 817 trace_nbd_negotiate_meta_query_skip("different lengths"); 818 return nbd_opt_skip(client, len, errp); 819 } 820 821 return nbd_meta_pattern(client, pattern, match, errp); 822 } 823 824 /* nbd_meta_base_query 825 * 826 * Handle queries to 'base' namespace. For now, only the base:allocation 827 * context is available. 'len' is the amount of text remaining to be read from 828 * the current name, after the 'base:' portion has been stripped. 829 * 830 * Return -errno on I/O error, 0 if option was completely handled by 831 * sending a reply about inconsistent lengths, or 1 on success. 832 */ 833 static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta, 834 uint32_t len, Error **errp) 835 { 836 return nbd_meta_empty_or_pattern(client, "allocation", len, 837 &meta->base_allocation, errp); 838 } 839 840 /* nbd_meta_bitmap_query 841 * 842 * Handle query to 'qemu:' namespace. 843 * @len is the amount of text remaining to be read from the current name, after 844 * the 'qemu:' portion has been stripped. 845 * 846 * Return -errno on I/O error, 0 if option was completely handled by 847 * sending a reply about inconsistent lengths, or 1 on success. */ 848 static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta, 849 uint32_t len, Error **errp) 850 { 851 bool dirty_bitmap = false; 852 size_t dirty_bitmap_len = strlen("dirty-bitmap:"); 853 int ret; 854 855 if (!meta->exp->export_bitmap) { 856 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported"); 857 return nbd_opt_skip(client, len, errp); 858 } 859 860 if (len == 0) { 861 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 862 meta->bitmap = true; 863 } 864 trace_nbd_negotiate_meta_query_parse("empty"); 865 return 1; 866 } 867 868 if (len < dirty_bitmap_len) { 869 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 870 return nbd_opt_skip(client, len, errp); 871 } 872 873 len -= dirty_bitmap_len; 874 ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp); 875 if (ret <= 0) { 876 return ret; 877 } 878 if (!dirty_bitmap) { 879 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 880 return nbd_opt_skip(client, len, errp); 881 } 882 883 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); 884 885 return nbd_meta_empty_or_pattern( 886 client, meta->exp->export_bitmap_context + 887 strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp); 888 } 889 890 /* nbd_negotiate_meta_query 891 * 892 * Parse namespace name and call corresponding function to parse body of the 893 * query. 894 * 895 * The only supported namespace now is 'base'. 896 * 897 * The function aims not wasting time and memory to read long unknown namespace 898 * names. 899 * 900 * Return -errno on I/O error, 0 if option was completely handled by 901 * sending a reply about inconsistent lengths, or 1 on success. */ 902 static int nbd_negotiate_meta_query(NBDClient *client, 903 NBDExportMetaContexts *meta, Error **errp) 904 { 905 /* 906 * Both 'qemu' and 'base' namespaces have length = 5 including a 907 * colon. If another length namespace is later introduced, this 908 * should certainly be refactored. 909 */ 910 int ret; 911 size_t ns_len = 5; 912 char ns[5]; 913 uint32_t len; 914 915 ret = nbd_opt_read(client, &len, sizeof(len), errp); 916 if (ret <= 0) { 917 return ret; 918 } 919 len = cpu_to_be32(len); 920 921 if (len < ns_len) { 922 trace_nbd_negotiate_meta_query_skip("length too short"); 923 return nbd_opt_skip(client, len, errp); 924 } 925 926 len -= ns_len; 927 ret = nbd_opt_read(client, ns, ns_len, errp); 928 if (ret <= 0) { 929 return ret; 930 } 931 932 if (!strncmp(ns, "base:", ns_len)) { 933 trace_nbd_negotiate_meta_query_parse("base:"); 934 return nbd_meta_base_query(client, meta, len, errp); 935 } else if (!strncmp(ns, "qemu:", ns_len)) { 936 trace_nbd_negotiate_meta_query_parse("qemu:"); 937 return nbd_meta_qemu_query(client, meta, len, errp); 938 } 939 940 trace_nbd_negotiate_meta_query_skip("unknown namespace"); 941 return nbd_opt_skip(client, len, errp); 942 } 943 944 /* nbd_negotiate_meta_queries 945 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT 946 * 947 * Return -errno on I/O error, or 0 if option was completely handled. */ 948 static int nbd_negotiate_meta_queries(NBDClient *client, 949 NBDExportMetaContexts *meta, Error **errp) 950 { 951 int ret; 952 char export_name[NBD_MAX_NAME_SIZE + 1]; 953 NBDExportMetaContexts local_meta; 954 uint32_t nb_queries; 955 int i; 956 957 if (!client->structured_reply) { 958 return nbd_opt_invalid(client, errp, 959 "request option '%s' when structured reply " 960 "is not negotiated", 961 nbd_opt_lookup(client->opt)); 962 } 963 964 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 965 /* Only change the caller's meta on SET. */ 966 meta = &local_meta; 967 } 968 969 memset(meta, 0, sizeof(*meta)); 970 971 ret = nbd_opt_read_name(client, export_name, NULL, errp); 972 if (ret <= 0) { 973 return ret; 974 } 975 976 meta->exp = nbd_export_find(export_name); 977 if (meta->exp == NULL) { 978 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, 979 "export '%s' not present", export_name); 980 } 981 982 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp); 983 if (ret <= 0) { 984 return ret; 985 } 986 nb_queries = cpu_to_be32(nb_queries); 987 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), 988 export_name, nb_queries); 989 990 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { 991 /* enable all known contexts */ 992 meta->base_allocation = true; 993 meta->bitmap = !!meta->exp->export_bitmap; 994 } else { 995 for (i = 0; i < nb_queries; ++i) { 996 ret = nbd_negotiate_meta_query(client, meta, errp); 997 if (ret <= 0) { 998 return ret; 999 } 1000 } 1001 } 1002 1003 if (meta->base_allocation) { 1004 ret = nbd_negotiate_send_meta_context(client, "base:allocation", 1005 NBD_META_ID_BASE_ALLOCATION, 1006 errp); 1007 if (ret < 0) { 1008 return ret; 1009 } 1010 } 1011 1012 if (meta->bitmap) { 1013 ret = nbd_negotiate_send_meta_context(client, 1014 meta->exp->export_bitmap_context, 1015 NBD_META_ID_DIRTY_BITMAP, 1016 errp); 1017 if (ret < 0) { 1018 return ret; 1019 } 1020 } 1021 1022 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1023 if (ret == 0) { 1024 meta->valid = true; 1025 } 1026 1027 return ret; 1028 } 1029 1030 /* nbd_negotiate_options 1031 * Process all NBD_OPT_* client option commands, during fixed newstyle 1032 * negotiation. 1033 * Return: 1034 * -errno on error, errp is set 1035 * 0 on successful negotiation, errp is not set 1036 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1037 * errp is not set 1038 */ 1039 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags, 1040 Error **errp) 1041 { 1042 uint32_t flags; 1043 bool fixedNewstyle = false; 1044 bool no_zeroes = false; 1045 1046 /* Client sends: 1047 [ 0 .. 3] client flags 1048 1049 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 1050 [ 0 .. 7] NBD_OPTS_MAGIC 1051 [ 8 .. 11] NBD option 1052 [12 .. 15] Data length 1053 ... Rest of request 1054 1055 [ 0 .. 7] NBD_OPTS_MAGIC 1056 [ 8 .. 11] Second NBD option 1057 [12 .. 15] Data length 1058 ... Rest of request 1059 */ 1060 1061 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) { 1062 return -EIO; 1063 } 1064 trace_nbd_negotiate_options_flags(flags); 1065 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1066 fixedNewstyle = true; 1067 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1068 } 1069 if (flags & NBD_FLAG_C_NO_ZEROES) { 1070 no_zeroes = true; 1071 flags &= ~NBD_FLAG_C_NO_ZEROES; 1072 } 1073 if (flags != 0) { 1074 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1075 return -EINVAL; 1076 } 1077 1078 while (1) { 1079 int ret; 1080 uint32_t option, length; 1081 uint64_t magic; 1082 1083 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) { 1084 return -EINVAL; 1085 } 1086 trace_nbd_negotiate_options_check_magic(magic); 1087 if (magic != NBD_OPTS_MAGIC) { 1088 error_setg(errp, "Bad magic received"); 1089 return -EINVAL; 1090 } 1091 1092 if (nbd_read32(client->ioc, &option, "option", errp) < 0) { 1093 return -EINVAL; 1094 } 1095 client->opt = option; 1096 1097 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) { 1098 return -EINVAL; 1099 } 1100 assert(!client->optlen); 1101 client->optlen = length; 1102 1103 if (length > NBD_MAX_BUFFER_SIZE) { 1104 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1105 length, NBD_MAX_BUFFER_SIZE); 1106 return -EINVAL; 1107 } 1108 1109 trace_nbd_negotiate_options_check_option(option, 1110 nbd_opt_lookup(option)); 1111 if (client->tlscreds && 1112 client->ioc == (QIOChannel *)client->sioc) { 1113 QIOChannel *tioc; 1114 if (!fixedNewstyle) { 1115 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1116 return -EINVAL; 1117 } 1118 switch (option) { 1119 case NBD_OPT_STARTTLS: 1120 if (length) { 1121 /* Unconditionally drop the connection if the client 1122 * can't start a TLS negotiation correctly */ 1123 return nbd_reject_length(client, true, errp); 1124 } 1125 tioc = nbd_negotiate_handle_starttls(client, errp); 1126 if (!tioc) { 1127 return -EIO; 1128 } 1129 ret = 0; 1130 object_unref(OBJECT(client->ioc)); 1131 client->ioc = QIO_CHANNEL(tioc); 1132 break; 1133 1134 case NBD_OPT_EXPORT_NAME: 1135 /* No way to return an error to client, so drop connection */ 1136 error_setg(errp, "Option 0x%x not permitted before TLS", 1137 option); 1138 return -EINVAL; 1139 1140 default: 1141 /* Let the client keep trying, unless they asked to 1142 * quit. Always try to give an error back to the 1143 * client; but when replying to OPT_ABORT, be aware 1144 * that the client may hang up before receiving the 1145 * error, in which case we are fine ignoring the 1146 * resulting EPIPE. */ 1147 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, 1148 option == NBD_OPT_ABORT ? NULL : errp, 1149 "Option 0x%" PRIx32 1150 " not permitted before TLS", option); 1151 if (option == NBD_OPT_ABORT) { 1152 return 1; 1153 } 1154 break; 1155 } 1156 } else if (fixedNewstyle) { 1157 switch (option) { 1158 case NBD_OPT_LIST: 1159 if (length) { 1160 ret = nbd_reject_length(client, false, errp); 1161 } else { 1162 ret = nbd_negotiate_handle_list(client, errp); 1163 } 1164 break; 1165 1166 case NBD_OPT_ABORT: 1167 /* NBD spec says we must try to reply before 1168 * disconnecting, but that we must also tolerate 1169 * guests that don't wait for our reply. */ 1170 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1171 return 1; 1172 1173 case NBD_OPT_EXPORT_NAME: 1174 return nbd_negotiate_handle_export_name(client, 1175 myflags, no_zeroes, 1176 errp); 1177 1178 case NBD_OPT_INFO: 1179 case NBD_OPT_GO: 1180 ret = nbd_negotiate_handle_info(client, myflags, errp); 1181 if (ret == 1) { 1182 assert(option == NBD_OPT_GO); 1183 return 0; 1184 } 1185 break; 1186 1187 case NBD_OPT_STARTTLS: 1188 if (length) { 1189 ret = nbd_reject_length(client, false, errp); 1190 } else if (client->tlscreds) { 1191 ret = nbd_negotiate_send_rep_err(client, 1192 NBD_REP_ERR_INVALID, errp, 1193 "TLS already enabled"); 1194 } else { 1195 ret = nbd_negotiate_send_rep_err(client, 1196 NBD_REP_ERR_POLICY, errp, 1197 "TLS not configured"); 1198 } 1199 break; 1200 1201 case NBD_OPT_STRUCTURED_REPLY: 1202 if (length) { 1203 ret = nbd_reject_length(client, false, errp); 1204 } else if (client->structured_reply) { 1205 ret = nbd_negotiate_send_rep_err( 1206 client, NBD_REP_ERR_INVALID, errp, 1207 "structured reply already negotiated"); 1208 } else { 1209 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1210 client->structured_reply = true; 1211 myflags |= NBD_FLAG_SEND_DF; 1212 } 1213 break; 1214 1215 case NBD_OPT_LIST_META_CONTEXT: 1216 case NBD_OPT_SET_META_CONTEXT: 1217 ret = nbd_negotiate_meta_queries(client, &client->export_meta, 1218 errp); 1219 break; 1220 1221 default: 1222 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1223 "Unsupported option %" PRIu32 " (%s)", 1224 option, nbd_opt_lookup(option)); 1225 break; 1226 } 1227 } else { 1228 /* 1229 * If broken new-style we should drop the connection 1230 * for anything except NBD_OPT_EXPORT_NAME 1231 */ 1232 switch (option) { 1233 case NBD_OPT_EXPORT_NAME: 1234 return nbd_negotiate_handle_export_name(client, 1235 myflags, no_zeroes, 1236 errp); 1237 1238 default: 1239 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1240 option, nbd_opt_lookup(option)); 1241 return -EINVAL; 1242 } 1243 } 1244 if (ret < 0) { 1245 return ret; 1246 } 1247 } 1248 } 1249 1250 /* nbd_negotiate 1251 * Return: 1252 * -errno on error, errp is set 1253 * 0 on successful negotiation, errp is not set 1254 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1255 * errp is not set 1256 */ 1257 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1258 { 1259 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1260 int ret; 1261 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | 1262 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA | 1263 NBD_FLAG_SEND_WRITE_ZEROES | NBD_FLAG_SEND_CACHE); 1264 1265 /* Old style negotiation header, no room for options 1266 [ 0 .. 7] passwd ("NBDMAGIC") 1267 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1268 [16 .. 23] size 1269 [24 .. 27] export flags (zero-extended) 1270 [28 .. 151] reserved (0) 1271 1272 New style negotiation header, client can send options 1273 [ 0 .. 7] passwd ("NBDMAGIC") 1274 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1275 [16 .. 17] server flags (0) 1276 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1277 */ 1278 1279 qio_channel_set_blocking(client->ioc, false, NULL); 1280 1281 trace_nbd_negotiate_begin(); 1282 memcpy(buf, "NBDMAGIC", 8); 1283 1284 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1285 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1286 1287 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 1288 error_prepend(errp, "write failed: "); 1289 return -EINVAL; 1290 } 1291 ret = nbd_negotiate_options(client, myflags, errp); 1292 if (ret != 0) { 1293 if (ret < 0) { 1294 error_prepend(errp, "option negotiation failed: "); 1295 } 1296 return ret; 1297 } 1298 1299 assert(!client->optlen); 1300 trace_nbd_negotiate_success(); 1301 1302 return 0; 1303 } 1304 1305 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 1306 Error **errp) 1307 { 1308 uint8_t buf[NBD_REQUEST_SIZE]; 1309 uint32_t magic; 1310 int ret; 1311 1312 ret = nbd_read(ioc, buf, sizeof(buf), "request", errp); 1313 if (ret < 0) { 1314 return ret; 1315 } 1316 1317 /* Request 1318 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1319 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1320 [ 6 .. 7] type (NBD_CMD_READ, ...) 1321 [ 8 .. 15] handle 1322 [16 .. 23] from 1323 [24 .. 27] len 1324 */ 1325 1326 magic = ldl_be_p(buf); 1327 request->flags = lduw_be_p(buf + 4); 1328 request->type = lduw_be_p(buf + 6); 1329 request->handle = ldq_be_p(buf + 8); 1330 request->from = ldq_be_p(buf + 16); 1331 request->len = ldl_be_p(buf + 24); 1332 1333 trace_nbd_receive_request(magic, request->flags, request->type, 1334 request->from, request->len); 1335 1336 if (magic != NBD_REQUEST_MAGIC) { 1337 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 1338 return -EINVAL; 1339 } 1340 return 0; 1341 } 1342 1343 #define MAX_NBD_REQUESTS 16 1344 1345 void nbd_client_get(NBDClient *client) 1346 { 1347 client->refcount++; 1348 } 1349 1350 void nbd_client_put(NBDClient *client) 1351 { 1352 if (--client->refcount == 0) { 1353 /* The last reference should be dropped by client->close, 1354 * which is called by client_close. 1355 */ 1356 assert(client->closing); 1357 1358 qio_channel_detach_aio_context(client->ioc); 1359 object_unref(OBJECT(client->sioc)); 1360 object_unref(OBJECT(client->ioc)); 1361 if (client->tlscreds) { 1362 object_unref(OBJECT(client->tlscreds)); 1363 } 1364 g_free(client->tlsauthz); 1365 if (client->exp) { 1366 QTAILQ_REMOVE(&client->exp->clients, client, next); 1367 nbd_export_put(client->exp); 1368 } 1369 g_free(client); 1370 } 1371 } 1372 1373 static void client_close(NBDClient *client, bool negotiated) 1374 { 1375 if (client->closing) { 1376 return; 1377 } 1378 1379 client->closing = true; 1380 1381 /* Force requests to finish. They will drop their own references, 1382 * then we'll close the socket and free the NBDClient. 1383 */ 1384 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1385 NULL); 1386 1387 /* Also tell the client, so that they release their reference. */ 1388 if (client->close_fn) { 1389 client->close_fn(client, negotiated); 1390 } 1391 } 1392 1393 static NBDRequestData *nbd_request_get(NBDClient *client) 1394 { 1395 NBDRequestData *req; 1396 1397 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1398 client->nb_requests++; 1399 1400 req = g_new0(NBDRequestData, 1); 1401 nbd_client_get(client); 1402 req->client = client; 1403 return req; 1404 } 1405 1406 static void nbd_request_put(NBDRequestData *req) 1407 { 1408 NBDClient *client = req->client; 1409 1410 if (req->data) { 1411 qemu_vfree(req->data); 1412 } 1413 g_free(req); 1414 1415 client->nb_requests--; 1416 nbd_client_receive_next_request(client); 1417 1418 nbd_client_put(client); 1419 } 1420 1421 static void blk_aio_attached(AioContext *ctx, void *opaque) 1422 { 1423 NBDExport *exp = opaque; 1424 NBDClient *client; 1425 1426 trace_nbd_blk_aio_attached(exp->name, ctx); 1427 1428 exp->ctx = ctx; 1429 1430 QTAILQ_FOREACH(client, &exp->clients, next) { 1431 qio_channel_attach_aio_context(client->ioc, ctx); 1432 if (client->recv_coroutine) { 1433 aio_co_schedule(ctx, client->recv_coroutine); 1434 } 1435 if (client->send_coroutine) { 1436 aio_co_schedule(ctx, client->send_coroutine); 1437 } 1438 } 1439 } 1440 1441 static void blk_aio_detach(void *opaque) 1442 { 1443 NBDExport *exp = opaque; 1444 NBDClient *client; 1445 1446 trace_nbd_blk_aio_detach(exp->name, exp->ctx); 1447 1448 QTAILQ_FOREACH(client, &exp->clients, next) { 1449 qio_channel_detach_aio_context(client->ioc); 1450 } 1451 1452 exp->ctx = NULL; 1453 } 1454 1455 static void nbd_eject_notifier(Notifier *n, void *data) 1456 { 1457 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1458 nbd_export_close(exp); 1459 } 1460 1461 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset, 1462 uint64_t size, const char *name, const char *desc, 1463 const char *bitmap, uint16_t nbdflags, 1464 void (*close)(NBDExport *), bool writethrough, 1465 BlockBackend *on_eject_blk, Error **errp) 1466 { 1467 AioContext *ctx; 1468 BlockBackend *blk; 1469 NBDExport *exp = g_new0(NBDExport, 1); 1470 uint64_t perm; 1471 int ret; 1472 1473 /* 1474 * NBD exports are used for non-shared storage migration. Make sure 1475 * that BDRV_O_INACTIVE is cleared and the image is ready for write 1476 * access since the export could be available before migration handover. 1477 */ 1478 assert(name); 1479 ctx = bdrv_get_aio_context(bs); 1480 aio_context_acquire(ctx); 1481 bdrv_invalidate_cache(bs, NULL); 1482 aio_context_release(ctx); 1483 1484 /* Don't allow resize while the NBD server is running, otherwise we don't 1485 * care what happens with the node. */ 1486 perm = BLK_PERM_CONSISTENT_READ; 1487 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) { 1488 perm |= BLK_PERM_WRITE; 1489 } 1490 blk = blk_new(bdrv_get_aio_context(bs), perm, 1491 BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1492 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); 1493 ret = blk_insert_bs(blk, bs, errp); 1494 if (ret < 0) { 1495 goto fail; 1496 } 1497 blk_set_enable_write_cache(blk, !writethrough); 1498 blk_set_allow_aio_context_change(blk, true); 1499 1500 exp->refcount = 1; 1501 QTAILQ_INIT(&exp->clients); 1502 exp->blk = blk; 1503 assert(dev_offset <= INT64_MAX); 1504 exp->dev_offset = dev_offset; 1505 exp->name = g_strdup(name); 1506 exp->description = g_strdup(desc); 1507 exp->nbdflags = nbdflags; 1508 assert(size <= INT64_MAX - dev_offset); 1509 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); 1510 1511 if (bitmap) { 1512 BdrvDirtyBitmap *bm = NULL; 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 (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) { 1529 goto fail; 1530 } 1531 1532 if ((nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) && 1533 bdrv_dirty_bitmap_enabled(bm)) { 1534 error_setg(errp, 1535 "Enabled bitmap '%s' incompatible with readonly export", 1536 bitmap); 1537 goto fail; 1538 } 1539 1540 bdrv_dirty_bitmap_set_busy(bm, true); 1541 exp->export_bitmap = bm; 1542 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s", 1543 bitmap); 1544 } 1545 1546 exp->close = close; 1547 exp->ctx = blk_get_aio_context(blk); 1548 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1549 1550 if (on_eject_blk) { 1551 blk_ref(on_eject_blk); 1552 exp->eject_notifier_blk = on_eject_blk; 1553 exp->eject_notifier.notify = nbd_eject_notifier; 1554 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier); 1555 } 1556 QTAILQ_INSERT_TAIL(&exports, exp, next); 1557 nbd_export_get(exp); 1558 return exp; 1559 1560 fail: 1561 blk_unref(blk); 1562 g_free(exp->name); 1563 g_free(exp->description); 1564 g_free(exp); 1565 return NULL; 1566 } 1567 1568 NBDExport *nbd_export_find(const char *name) 1569 { 1570 NBDExport *exp; 1571 QTAILQ_FOREACH(exp, &exports, next) { 1572 if (strcmp(name, exp->name) == 0) { 1573 return exp; 1574 } 1575 } 1576 1577 return NULL; 1578 } 1579 1580 void nbd_export_close(NBDExport *exp) 1581 { 1582 NBDClient *client, *next; 1583 1584 nbd_export_get(exp); 1585 /* 1586 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a 1587 * close mode that stops advertising the export to new clients but 1588 * still permits existing clients to run to completion? Because of 1589 * that possibility, nbd_export_close() can be called more than 1590 * once on an export. 1591 */ 1592 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1593 client_close(client, true); 1594 } 1595 if (exp->name) { 1596 nbd_export_put(exp); 1597 g_free(exp->name); 1598 exp->name = NULL; 1599 QTAILQ_REMOVE(&exports, exp, next); 1600 } 1601 g_free(exp->description); 1602 exp->description = NULL; 1603 nbd_export_put(exp); 1604 } 1605 1606 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp) 1607 { 1608 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) { 1609 nbd_export_close(exp); 1610 return; 1611 } 1612 1613 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE); 1614 1615 error_setg(errp, "export '%s' still in use", exp->name); 1616 error_append_hint(errp, "Use mode='hard' to force client disconnect\n"); 1617 } 1618 1619 void nbd_export_get(NBDExport *exp) 1620 { 1621 assert(exp->refcount > 0); 1622 exp->refcount++; 1623 } 1624 1625 void nbd_export_put(NBDExport *exp) 1626 { 1627 assert(exp->refcount > 0); 1628 if (exp->refcount == 1) { 1629 nbd_export_close(exp); 1630 } 1631 1632 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen 1633 * if someone calls nbd_export_put() on named export not through 1634 * nbd_export_set_name() when refcount is 1. So, let's assert that 1635 * it is > 0. 1636 */ 1637 assert(exp->refcount > 0); 1638 if (--exp->refcount == 0) { 1639 assert(exp->name == NULL); 1640 assert(exp->description == NULL); 1641 1642 if (exp->close) { 1643 exp->close(exp); 1644 } 1645 1646 if (exp->blk) { 1647 if (exp->eject_notifier_blk) { 1648 notifier_remove(&exp->eject_notifier); 1649 blk_unref(exp->eject_notifier_blk); 1650 } 1651 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, 1652 blk_aio_detach, exp); 1653 blk_unref(exp->blk); 1654 exp->blk = NULL; 1655 } 1656 1657 if (exp->export_bitmap) { 1658 bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false); 1659 g_free(exp->export_bitmap_context); 1660 } 1661 1662 g_free(exp); 1663 } 1664 } 1665 1666 BlockBackend *nbd_export_get_blockdev(NBDExport *exp) 1667 { 1668 return exp->blk; 1669 } 1670 1671 void nbd_export_close_all(void) 1672 { 1673 NBDExport *exp, *next; 1674 1675 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { 1676 nbd_export_close(exp); 1677 } 1678 } 1679 1680 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1681 unsigned niov, Error **errp) 1682 { 1683 int ret; 1684 1685 g_assert(qemu_in_coroutine()); 1686 qemu_co_mutex_lock(&client->send_lock); 1687 client->send_coroutine = qemu_coroutine_self(); 1688 1689 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1690 1691 client->send_coroutine = NULL; 1692 qemu_co_mutex_unlock(&client->send_lock); 1693 1694 return ret; 1695 } 1696 1697 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1698 uint64_t handle) 1699 { 1700 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1701 stl_be_p(&reply->error, error); 1702 stq_be_p(&reply->handle, handle); 1703 } 1704 1705 static int nbd_co_send_simple_reply(NBDClient *client, 1706 uint64_t handle, 1707 uint32_t error, 1708 void *data, 1709 size_t len, 1710 Error **errp) 1711 { 1712 NBDSimpleReply reply; 1713 int nbd_err = system_errno_to_nbd_errno(error); 1714 struct iovec iov[] = { 1715 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1716 {.iov_base = data, .iov_len = len} 1717 }; 1718 1719 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1720 len); 1721 set_be_simple_reply(&reply, nbd_err, handle); 1722 1723 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1724 } 1725 1726 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1727 uint16_t type, uint64_t handle, uint32_t length) 1728 { 1729 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1730 stw_be_p(&chunk->flags, flags); 1731 stw_be_p(&chunk->type, type); 1732 stq_be_p(&chunk->handle, handle); 1733 stl_be_p(&chunk->length, length); 1734 } 1735 1736 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1737 uint64_t handle, 1738 Error **errp) 1739 { 1740 NBDStructuredReplyChunk chunk; 1741 struct iovec iov[] = { 1742 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1743 }; 1744 1745 trace_nbd_co_send_structured_done(handle); 1746 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1747 1748 return nbd_co_send_iov(client, iov, 1, errp); 1749 } 1750 1751 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1752 uint64_t handle, 1753 uint64_t offset, 1754 void *data, 1755 size_t size, 1756 bool final, 1757 Error **errp) 1758 { 1759 NBDStructuredReadData chunk; 1760 struct iovec iov[] = { 1761 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1762 {.iov_base = data, .iov_len = size} 1763 }; 1764 1765 assert(size); 1766 trace_nbd_co_send_structured_read(handle, offset, data, size); 1767 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1768 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1769 sizeof(chunk) - sizeof(chunk.h) + size); 1770 stq_be_p(&chunk.offset, offset); 1771 1772 return nbd_co_send_iov(client, iov, 2, errp); 1773 } 1774 1775 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1776 uint64_t handle, 1777 uint32_t error, 1778 const char *msg, 1779 Error **errp) 1780 { 1781 NBDStructuredError chunk; 1782 int nbd_err = system_errno_to_nbd_errno(error); 1783 struct iovec iov[] = { 1784 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1785 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1786 }; 1787 1788 assert(nbd_err); 1789 trace_nbd_co_send_structured_error(handle, nbd_err, 1790 nbd_err_lookup(nbd_err), msg ? msg : ""); 1791 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1792 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1793 stl_be_p(&chunk.error, nbd_err); 1794 stw_be_p(&chunk.message_length, iov[1].iov_len); 1795 1796 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1797 } 1798 1799 /* Do a sparse read and send the structured reply to the client. 1800 * Returns -errno if sending fails. bdrv_block_status_above() failure is 1801 * reported to the client, at which point this function succeeds. 1802 */ 1803 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1804 uint64_t handle, 1805 uint64_t offset, 1806 uint8_t *data, 1807 size_t size, 1808 Error **errp) 1809 { 1810 int ret = 0; 1811 NBDExport *exp = client->exp; 1812 size_t progress = 0; 1813 1814 while (progress < size) { 1815 int64_t pnum; 1816 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL, 1817 offset + progress, 1818 size - progress, &pnum, NULL, 1819 NULL); 1820 bool final; 1821 1822 if (status < 0) { 1823 char *msg = g_strdup_printf("unable to check for holes: %s", 1824 strerror(-status)); 1825 1826 ret = nbd_co_send_structured_error(client, handle, -status, msg, 1827 errp); 1828 g_free(msg); 1829 return ret; 1830 } 1831 assert(pnum && pnum <= size - progress); 1832 final = progress + pnum == size; 1833 if (status & BDRV_BLOCK_ZERO) { 1834 NBDStructuredReadHole chunk; 1835 struct iovec iov[] = { 1836 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1837 }; 1838 1839 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1840 pnum); 1841 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1842 NBD_REPLY_TYPE_OFFSET_HOLE, 1843 handle, sizeof(chunk) - sizeof(chunk.h)); 1844 stq_be_p(&chunk.offset, offset + progress); 1845 stl_be_p(&chunk.length, pnum); 1846 ret = nbd_co_send_iov(client, iov, 1, errp); 1847 } else { 1848 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset, 1849 data + progress, pnum); 1850 if (ret < 0) { 1851 error_setg_errno(errp, -ret, "reading from file failed"); 1852 break; 1853 } 1854 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1855 data + progress, pnum, final, 1856 errp); 1857 } 1858 1859 if (ret < 0) { 1860 break; 1861 } 1862 progress += pnum; 1863 } 1864 return ret; 1865 } 1866 1867 /* 1868 * Populate @extents from block status. Update @bytes to be the actual 1869 * length encoded (which may be smaller than the original), and update 1870 * @nb_extents to the number of extents used. 1871 * 1872 * Returns zero on success and -errno on bdrv_block_status_above failure. 1873 */ 1874 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, 1875 uint64_t *bytes, NBDExtent *extents, 1876 unsigned int *nb_extents) 1877 { 1878 uint64_t remaining_bytes = *bytes; 1879 NBDExtent *extent = extents, *extents_end = extents + *nb_extents; 1880 bool first_extent = true; 1881 1882 assert(*nb_extents); 1883 while (remaining_bytes) { 1884 uint32_t flags; 1885 int64_t num; 1886 int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes, 1887 &num, NULL, NULL); 1888 1889 if (ret < 0) { 1890 return ret; 1891 } 1892 1893 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) | 1894 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 1895 1896 if (first_extent) { 1897 extent->flags = flags; 1898 extent->length = num; 1899 first_extent = false; 1900 } else if (flags == extent->flags) { 1901 /* extend current extent */ 1902 extent->length += num; 1903 } else { 1904 if (extent + 1 == extents_end) { 1905 break; 1906 } 1907 1908 /* start new extent */ 1909 extent++; 1910 extent->flags = flags; 1911 extent->length = num; 1912 } 1913 offset += num; 1914 remaining_bytes -= num; 1915 } 1916 1917 extents_end = extent + 1; 1918 1919 for (extent = extents; extent < extents_end; extent++) { 1920 extent->flags = cpu_to_be32(extent->flags); 1921 extent->length = cpu_to_be32(extent->length); 1922 } 1923 1924 *bytes -= remaining_bytes; 1925 *nb_extents = extents_end - extents; 1926 1927 return 0; 1928 } 1929 1930 /* nbd_co_send_extents 1931 * 1932 * @length is only for tracing purposes (and may be smaller or larger 1933 * than the client's original request). @last controls whether 1934 * NBD_REPLY_FLAG_DONE is sent. @extents should already be in 1935 * big-endian format. 1936 */ 1937 static int nbd_co_send_extents(NBDClient *client, uint64_t handle, 1938 NBDExtent *extents, unsigned int nb_extents, 1939 uint64_t length, bool last, 1940 uint32_t context_id, Error **errp) 1941 { 1942 NBDStructuredMeta chunk; 1943 1944 struct iovec iov[] = { 1945 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1946 {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])} 1947 }; 1948 1949 trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last); 1950 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0, 1951 NBD_REPLY_TYPE_BLOCK_STATUS, 1952 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1953 stl_be_p(&chunk.context_id, context_id); 1954 1955 return nbd_co_send_iov(client, iov, 2, errp); 1956 } 1957 1958 /* Get block status from the exported device and send it to the client */ 1959 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, 1960 BlockDriverState *bs, uint64_t offset, 1961 uint32_t length, bool dont_fragment, 1962 bool last, uint32_t context_id, 1963 Error **errp) 1964 { 1965 int ret; 1966 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 1967 NBDExtent *extents = g_new(NBDExtent, nb_extents); 1968 uint64_t final_length = length; 1969 1970 ret = blockstatus_to_extents(bs, offset, &final_length, extents, 1971 &nb_extents); 1972 if (ret < 0) { 1973 g_free(extents); 1974 return nbd_co_send_structured_error( 1975 client, handle, -ret, "can't get block status", errp); 1976 } 1977 1978 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 1979 final_length, last, context_id, errp); 1980 1981 g_free(extents); 1982 1983 return ret; 1984 } 1985 1986 /* 1987 * Populate @extents from a dirty bitmap. Unless @dont_fragment, the 1988 * final extent may exceed the original @length. Store in @length the 1989 * byte length encoded (which may be smaller or larger than the 1990 * original), and return the number of extents used. 1991 */ 1992 static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset, 1993 uint64_t *length, NBDExtent *extents, 1994 unsigned int nb_extents, 1995 bool dont_fragment) 1996 { 1997 uint64_t begin = offset, end = offset; 1998 uint64_t overall_end = offset + *length; 1999 unsigned int i = 0; 2000 BdrvDirtyBitmapIter *it; 2001 bool dirty; 2002 2003 bdrv_dirty_bitmap_lock(bitmap); 2004 2005 it = bdrv_dirty_iter_new(bitmap); 2006 dirty = bdrv_get_dirty_locked(NULL, bitmap, offset); 2007 2008 assert(begin < overall_end && nb_extents); 2009 while (begin < overall_end && i < nb_extents) { 2010 bool next_dirty = !dirty; 2011 2012 if (dirty) { 2013 end = bdrv_dirty_bitmap_next_zero(bitmap, begin, UINT64_MAX); 2014 } else { 2015 bdrv_set_dirty_iter(it, begin); 2016 end = bdrv_dirty_iter_next(it); 2017 } 2018 if (end == -1 || end - begin > UINT32_MAX) { 2019 /* Cap to an aligned value < 4G beyond begin. */ 2020 end = MIN(bdrv_dirty_bitmap_size(bitmap), 2021 begin + UINT32_MAX + 1 - 2022 bdrv_dirty_bitmap_granularity(bitmap)); 2023 next_dirty = dirty; 2024 } 2025 if (dont_fragment && end > overall_end) { 2026 end = overall_end; 2027 } 2028 2029 extents[i].length = cpu_to_be32(end - begin); 2030 extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0); 2031 i++; 2032 begin = end; 2033 dirty = next_dirty; 2034 } 2035 2036 bdrv_dirty_iter_free(it); 2037 2038 bdrv_dirty_bitmap_unlock(bitmap); 2039 2040 assert(offset < end); 2041 *length = end - offset; 2042 return i; 2043 } 2044 2045 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, 2046 BdrvDirtyBitmap *bitmap, uint64_t offset, 2047 uint32_t length, bool dont_fragment, bool last, 2048 uint32_t context_id, Error **errp) 2049 { 2050 int ret; 2051 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2052 NBDExtent *extents = g_new(NBDExtent, nb_extents); 2053 uint64_t final_length = length; 2054 2055 nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents, 2056 nb_extents, dont_fragment); 2057 2058 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 2059 final_length, last, context_id, errp); 2060 2061 g_free(extents); 2062 2063 return ret; 2064 } 2065 2066 /* nbd_co_receive_request 2067 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2068 * connection right away, and any other negative value to report an error to 2069 * the client (although the caller may still need to disconnect after reporting 2070 * the error). 2071 */ 2072 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 2073 Error **errp) 2074 { 2075 NBDClient *client = req->client; 2076 int valid_flags; 2077 2078 g_assert(qemu_in_coroutine()); 2079 assert(client->recv_coroutine == qemu_coroutine_self()); 2080 if (nbd_receive_request(client->ioc, request, errp) < 0) { 2081 return -EIO; 2082 } 2083 2084 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 2085 nbd_cmd_lookup(request->type)); 2086 2087 if (request->type != NBD_CMD_WRITE) { 2088 /* No payload, we are ready to read the next request. */ 2089 req->complete = true; 2090 } 2091 2092 if (request->type == NBD_CMD_DISC) { 2093 /* Special case: we're going to disconnect without a reply, 2094 * whether or not flags, from, or len are bogus */ 2095 return -EIO; 2096 } 2097 2098 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE || 2099 request->type == NBD_CMD_CACHE) 2100 { 2101 if (request->len > NBD_MAX_BUFFER_SIZE) { 2102 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 2103 request->len, NBD_MAX_BUFFER_SIZE); 2104 return -EINVAL; 2105 } 2106 2107 req->data = blk_try_blockalign(client->exp->blk, request->len); 2108 if (req->data == NULL) { 2109 error_setg(errp, "No memory"); 2110 return -ENOMEM; 2111 } 2112 } 2113 if (request->type == NBD_CMD_WRITE) { 2114 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data", 2115 errp) < 0) 2116 { 2117 return -EIO; 2118 } 2119 req->complete = true; 2120 2121 trace_nbd_co_receive_request_payload_received(request->handle, 2122 request->len); 2123 } 2124 2125 /* Sanity checks. */ 2126 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 2127 (request->type == NBD_CMD_WRITE || 2128 request->type == NBD_CMD_WRITE_ZEROES || 2129 request->type == NBD_CMD_TRIM)) { 2130 error_setg(errp, "Export is read-only"); 2131 return -EROFS; 2132 } 2133 if (request->from > client->exp->size || 2134 request->len > client->exp->size - request->from) { 2135 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 2136 ", Size: %" PRIu64, request->from, request->len, 2137 client->exp->size); 2138 return (request->type == NBD_CMD_WRITE || 2139 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2140 } 2141 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len, 2142 client->check_align)) { 2143 /* 2144 * The block layer gracefully handles unaligned requests, but 2145 * it's still worth tracing client non-compliance 2146 */ 2147 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type), 2148 request->from, 2149 request->len, 2150 client->check_align); 2151 } 2152 valid_flags = NBD_CMD_FLAG_FUA; 2153 if (request->type == NBD_CMD_READ && client->structured_reply) { 2154 valid_flags |= NBD_CMD_FLAG_DF; 2155 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 2156 valid_flags |= NBD_CMD_FLAG_NO_HOLE; 2157 } else if (request->type == NBD_CMD_BLOCK_STATUS) { 2158 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2159 } 2160 if (request->flags & ~valid_flags) { 2161 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2162 nbd_cmd_lookup(request->type), request->flags); 2163 return -EINVAL; 2164 } 2165 2166 return 0; 2167 } 2168 2169 /* Send simple reply without a payload, or a structured error 2170 * @error_msg is ignored if @ret >= 0 2171 * Returns 0 if connection is still live, -errno on failure to talk to client 2172 */ 2173 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2174 uint64_t handle, 2175 int ret, 2176 const char *error_msg, 2177 Error **errp) 2178 { 2179 if (client->structured_reply && ret < 0) { 2180 return nbd_co_send_structured_error(client, handle, -ret, error_msg, 2181 errp); 2182 } else { 2183 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0, 2184 NULL, 0, errp); 2185 } 2186 } 2187 2188 /* Handle NBD_CMD_READ request. 2189 * Return -errno if sending fails. Other errors are reported directly to the 2190 * client as an error reply. */ 2191 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2192 uint8_t *data, Error **errp) 2193 { 2194 int ret; 2195 NBDExport *exp = client->exp; 2196 2197 assert(request->type == NBD_CMD_READ || request->type == NBD_CMD_CACHE); 2198 2199 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2200 if (request->flags & NBD_CMD_FLAG_FUA) { 2201 ret = blk_co_flush(exp->blk); 2202 if (ret < 0) { 2203 return nbd_send_generic_reply(client, request->handle, ret, 2204 "flush failed", errp); 2205 } 2206 } 2207 2208 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) && 2209 request->len && request->type != NBD_CMD_CACHE) 2210 { 2211 return nbd_co_send_sparse_read(client, request->handle, request->from, 2212 data, request->len, errp); 2213 } 2214 2215 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data, 2216 request->len); 2217 if (ret < 0 || request->type == NBD_CMD_CACHE) { 2218 return nbd_send_generic_reply(client, request->handle, ret, 2219 "reading from file failed", errp); 2220 } 2221 2222 if (client->structured_reply) { 2223 if (request->len) { 2224 return nbd_co_send_structured_read(client, request->handle, 2225 request->from, data, 2226 request->len, true, errp); 2227 } else { 2228 return nbd_co_send_structured_done(client, request->handle, errp); 2229 } 2230 } else { 2231 return nbd_co_send_simple_reply(client, request->handle, 0, 2232 data, request->len, errp); 2233 } 2234 } 2235 2236 /* Handle NBD request. 2237 * Return -errno if sending fails. Other errors are reported directly to the 2238 * client as an error reply. */ 2239 static coroutine_fn int nbd_handle_request(NBDClient *client, 2240 NBDRequest *request, 2241 uint8_t *data, Error **errp) 2242 { 2243 int ret; 2244 int flags; 2245 NBDExport *exp = client->exp; 2246 char *msg; 2247 2248 switch (request->type) { 2249 case NBD_CMD_READ: 2250 case NBD_CMD_CACHE: 2251 return nbd_do_cmd_read(client, request, data, errp); 2252 2253 case NBD_CMD_WRITE: 2254 flags = 0; 2255 if (request->flags & NBD_CMD_FLAG_FUA) { 2256 flags |= BDRV_REQ_FUA; 2257 } 2258 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset, 2259 data, request->len, flags); 2260 return nbd_send_generic_reply(client, request->handle, ret, 2261 "writing to file failed", errp); 2262 2263 case NBD_CMD_WRITE_ZEROES: 2264 flags = 0; 2265 if (request->flags & NBD_CMD_FLAG_FUA) { 2266 flags |= BDRV_REQ_FUA; 2267 } 2268 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2269 flags |= BDRV_REQ_MAY_UNMAP; 2270 } 2271 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset, 2272 request->len, flags); 2273 return nbd_send_generic_reply(client, request->handle, ret, 2274 "writing to file failed", errp); 2275 2276 case NBD_CMD_DISC: 2277 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2278 abort(); 2279 2280 case NBD_CMD_FLUSH: 2281 ret = blk_co_flush(exp->blk); 2282 return nbd_send_generic_reply(client, request->handle, ret, 2283 "flush failed", errp); 2284 2285 case NBD_CMD_TRIM: 2286 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset, 2287 request->len); 2288 if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) { 2289 ret = blk_co_flush(exp->blk); 2290 } 2291 return nbd_send_generic_reply(client, request->handle, ret, 2292 "discard failed", errp); 2293 2294 case NBD_CMD_BLOCK_STATUS: 2295 if (!request->len) { 2296 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2297 "need non-zero length", errp); 2298 } 2299 if (client->export_meta.valid && 2300 (client->export_meta.base_allocation || 2301 client->export_meta.bitmap)) 2302 { 2303 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2304 2305 if (client->export_meta.base_allocation) { 2306 ret = nbd_co_send_block_status(client, request->handle, 2307 blk_bs(exp->blk), request->from, 2308 request->len, dont_fragment, 2309 !client->export_meta.bitmap, 2310 NBD_META_ID_BASE_ALLOCATION, 2311 errp); 2312 if (ret < 0) { 2313 return ret; 2314 } 2315 } 2316 2317 if (client->export_meta.bitmap) { 2318 ret = nbd_co_send_bitmap(client, request->handle, 2319 client->exp->export_bitmap, 2320 request->from, request->len, 2321 dont_fragment, 2322 true, NBD_META_ID_DIRTY_BITMAP, errp); 2323 if (ret < 0) { 2324 return ret; 2325 } 2326 } 2327 2328 return ret; 2329 } else { 2330 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2331 "CMD_BLOCK_STATUS not negotiated", 2332 errp); 2333 } 2334 2335 default: 2336 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 2337 request->type); 2338 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg, 2339 errp); 2340 g_free(msg); 2341 return ret; 2342 } 2343 } 2344 2345 /* Owns a reference to the NBDClient passed as opaque. */ 2346 static coroutine_fn void nbd_trip(void *opaque) 2347 { 2348 NBDClient *client = opaque; 2349 NBDRequestData *req; 2350 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 2351 int ret; 2352 Error *local_err = NULL; 2353 2354 trace_nbd_trip(); 2355 if (client->closing) { 2356 nbd_client_put(client); 2357 return; 2358 } 2359 2360 req = nbd_request_get(client); 2361 ret = nbd_co_receive_request(req, &request, &local_err); 2362 client->recv_coroutine = NULL; 2363 2364 if (client->closing) { 2365 /* 2366 * The client may be closed when we are blocked in 2367 * nbd_co_receive_request() 2368 */ 2369 goto done; 2370 } 2371 2372 nbd_client_receive_next_request(client); 2373 if (ret == -EIO) { 2374 goto disconnect; 2375 } 2376 2377 if (ret < 0) { 2378 /* It wans't -EIO, so, according to nbd_co_receive_request() 2379 * semantics, we should return the error to the client. */ 2380 Error *export_err = local_err; 2381 2382 local_err = NULL; 2383 ret = nbd_send_generic_reply(client, request.handle, -EINVAL, 2384 error_get_pretty(export_err), &local_err); 2385 error_free(export_err); 2386 } else { 2387 ret = nbd_handle_request(client, &request, req->data, &local_err); 2388 } 2389 if (ret < 0) { 2390 error_prepend(&local_err, "Failed to send reply: "); 2391 goto disconnect; 2392 } 2393 2394 /* We must disconnect after NBD_CMD_WRITE if we did not 2395 * read the payload. 2396 */ 2397 if (!req->complete) { 2398 error_setg(&local_err, "Request handling failed in intermediate state"); 2399 goto disconnect; 2400 } 2401 2402 done: 2403 nbd_request_put(req); 2404 nbd_client_put(client); 2405 return; 2406 2407 disconnect: 2408 if (local_err) { 2409 error_reportf_err(local_err, "Disconnect client, due to: "); 2410 } 2411 nbd_request_put(req); 2412 client_close(client, true); 2413 nbd_client_put(client); 2414 } 2415 2416 static void nbd_client_receive_next_request(NBDClient *client) 2417 { 2418 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 2419 nbd_client_get(client); 2420 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 2421 aio_co_schedule(client->exp->ctx, client->recv_coroutine); 2422 } 2423 } 2424 2425 static coroutine_fn void nbd_co_client_start(void *opaque) 2426 { 2427 NBDClient *client = opaque; 2428 Error *local_err = NULL; 2429 2430 qemu_co_mutex_init(&client->send_lock); 2431 2432 if (nbd_negotiate(client, &local_err)) { 2433 if (local_err) { 2434 error_report_err(local_err); 2435 } 2436 client_close(client, false); 2437 return; 2438 } 2439 2440 nbd_client_receive_next_request(client); 2441 } 2442 2443 /* 2444 * Create a new client listener using the given channel @sioc. 2445 * Begin servicing it in a coroutine. When the connection closes, call 2446 * @close_fn with an indication of whether the client completed negotiation. 2447 */ 2448 void nbd_client_new(QIOChannelSocket *sioc, 2449 QCryptoTLSCreds *tlscreds, 2450 const char *tlsauthz, 2451 void (*close_fn)(NBDClient *, bool)) 2452 { 2453 NBDClient *client; 2454 Coroutine *co; 2455 2456 client = g_new0(NBDClient, 1); 2457 client->refcount = 1; 2458 client->tlscreds = tlscreds; 2459 if (tlscreds) { 2460 object_ref(OBJECT(client->tlscreds)); 2461 } 2462 client->tlsauthz = g_strdup(tlsauthz); 2463 client->sioc = sioc; 2464 object_ref(OBJECT(client->sioc)); 2465 client->ioc = QIO_CHANNEL(sioc); 2466 object_ref(OBJECT(client->ioc)); 2467 client->close_fn = close_fn; 2468 2469 co = qemu_coroutine_create(nbd_co_client_start, client); 2470 qemu_coroutine_enter(co); 2471 } 2472