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 uint32_t check_align; /* If non-zero, check for aligned client requests */ 128 129 bool structured_reply; 130 NBDExportMetaContexts export_meta; 131 132 uint32_t opt; /* Current option being negotiated */ 133 uint32_t optlen; /* remaining length of data in ioc for the option being 134 negotiated now */ 135 }; 136 137 static void nbd_client_receive_next_request(NBDClient *client); 138 139 /* Basic flow for negotiation 140 141 Server Client 142 Negotiate 143 144 or 145 146 Server Client 147 Negotiate #1 148 Option 149 Negotiate #2 150 151 ---- 152 153 followed by 154 155 Server Client 156 Request 157 Response 158 Request 159 Response 160 ... 161 ... 162 Request (type == 2) 163 164 */ 165 166 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option, 167 uint32_t type, uint32_t length) 168 { 169 stq_be_p(&rep->magic, NBD_REP_MAGIC); 170 stl_be_p(&rep->option, option); 171 stl_be_p(&rep->type, type); 172 stl_be_p(&rep->length, length); 173 } 174 175 /* Send a reply header, including length, but no payload. 176 * Return -errno on error, 0 on success. */ 177 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type, 178 uint32_t len, Error **errp) 179 { 180 NBDOptionReply rep; 181 182 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt), 183 type, nbd_rep_lookup(type), len); 184 185 assert(len < NBD_MAX_BUFFER_SIZE); 186 187 set_be_option_rep(&rep, client->opt, type, len); 188 return nbd_write(client->ioc, &rep, sizeof(rep), errp); 189 } 190 191 /* Send a reply header with default 0 length. 192 * Return -errno on error, 0 on success. */ 193 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type, 194 Error **errp) 195 { 196 return nbd_negotiate_send_rep_len(client, type, 0, errp); 197 } 198 199 /* Send an error reply. 200 * Return -errno on error, 0 on success. */ 201 static int GCC_FMT_ATTR(4, 0) 202 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, 203 Error **errp, const char *fmt, va_list va) 204 { 205 char *msg; 206 int ret; 207 size_t len; 208 209 msg = g_strdup_vprintf(fmt, va); 210 len = strlen(msg); 211 assert(len < 4096); 212 trace_nbd_negotiate_send_rep_err(msg); 213 ret = nbd_negotiate_send_rep_len(client, type, len, errp); 214 if (ret < 0) { 215 goto out; 216 } 217 if (nbd_write(client->ioc, msg, len, errp) < 0) { 218 error_prepend(errp, "write failed (error message): "); 219 ret = -EIO; 220 } else { 221 ret = 0; 222 } 223 224 out: 225 g_free(msg); 226 return ret; 227 } 228 229 /* Send an error reply. 230 * Return -errno on error, 0 on success. */ 231 static int GCC_FMT_ATTR(4, 5) 232 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type, 233 Error **errp, const char *fmt, ...) 234 { 235 va_list va; 236 int ret; 237 238 va_start(va, fmt); 239 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 240 va_end(va); 241 return ret; 242 } 243 244 /* Drop remainder of the current option, and send a reply with the 245 * given error type and message. Return -errno on read or write 246 * failure; or 0 if connection is still live. */ 247 static int GCC_FMT_ATTR(4, 0) 248 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp, 249 const char *fmt, va_list va) 250 { 251 int ret = nbd_drop(client->ioc, client->optlen, errp); 252 253 client->optlen = 0; 254 if (!ret) { 255 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 256 } 257 return ret; 258 } 259 260 static int GCC_FMT_ATTR(4, 5) 261 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp, 262 const char *fmt, ...) 263 { 264 int ret; 265 va_list va; 266 267 va_start(va, fmt); 268 ret = nbd_opt_vdrop(client, type, errp, fmt, va); 269 va_end(va); 270 271 return ret; 272 } 273 274 static int GCC_FMT_ATTR(3, 4) 275 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...) 276 { 277 int ret; 278 va_list va; 279 280 va_start(va, fmt); 281 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va); 282 va_end(va); 283 284 return ret; 285 } 286 287 /* Read size bytes from the unparsed payload of the current option. 288 * Return -errno on I/O error, 0 if option was completely handled by 289 * sending a reply about inconsistent lengths, or 1 on success. */ 290 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size, 291 Error **errp) 292 { 293 if (size > client->optlen) { 294 return nbd_opt_invalid(client, errp, 295 "Inconsistent lengths in option %s", 296 nbd_opt_lookup(client->opt)); 297 } 298 client->optlen -= size; 299 return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1; 300 } 301 302 /* Drop size bytes from the unparsed payload of the current option. 303 * Return -errno on I/O error, 0 if option was completely handled by 304 * sending a reply about inconsistent lengths, or 1 on success. */ 305 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp) 306 { 307 if (size > client->optlen) { 308 return nbd_opt_invalid(client, errp, 309 "Inconsistent lengths in option %s", 310 nbd_opt_lookup(client->opt)); 311 } 312 client->optlen -= size; 313 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1; 314 } 315 316 /* nbd_opt_read_name 317 * 318 * Read a string with the format: 319 * uint32_t len (<= NBD_MAX_NAME_SIZE) 320 * len bytes string (not 0-terminated) 321 * 322 * @name should be enough to store NBD_MAX_NAME_SIZE+1. 323 * If @length is non-null, it will be set to the actual string length. 324 * 325 * Return -errno on I/O error, 0 if option was completely handled by 326 * sending a reply about inconsistent lengths, or 1 on success. 327 */ 328 static int nbd_opt_read_name(NBDClient *client, char *name, uint32_t *length, 329 Error **errp) 330 { 331 int ret; 332 uint32_t len; 333 334 ret = nbd_opt_read(client, &len, sizeof(len), errp); 335 if (ret <= 0) { 336 return ret; 337 } 338 len = cpu_to_be32(len); 339 340 if (len > NBD_MAX_NAME_SIZE) { 341 return nbd_opt_invalid(client, errp, 342 "Invalid name length: %" PRIu32, len); 343 } 344 345 ret = nbd_opt_read(client, name, len, errp); 346 if (ret <= 0) { 347 return ret; 348 } 349 name[len] = '\0'; 350 351 if (length) { 352 *length = len; 353 } 354 355 return 1; 356 } 357 358 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 359 * Return -errno on error, 0 on success. */ 360 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, 361 Error **errp) 362 { 363 size_t name_len, desc_len; 364 uint32_t len; 365 const char *name = exp->name ? exp->name : ""; 366 const char *desc = exp->description ? exp->description : ""; 367 QIOChannel *ioc = client->ioc; 368 int ret; 369 370 trace_nbd_negotiate_send_rep_list(name, desc); 371 name_len = strlen(name); 372 desc_len = strlen(desc); 373 len = name_len + desc_len + sizeof(len); 374 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp); 375 if (ret < 0) { 376 return ret; 377 } 378 379 len = cpu_to_be32(name_len); 380 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 381 error_prepend(errp, "write failed (name length): "); 382 return -EINVAL; 383 } 384 385 if (nbd_write(ioc, name, name_len, errp) < 0) { 386 error_prepend(errp, "write failed (name buffer): "); 387 return -EINVAL; 388 } 389 390 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 391 error_prepend(errp, "write failed (description buffer): "); 392 return -EINVAL; 393 } 394 395 return 0; 396 } 397 398 /* Process the NBD_OPT_LIST command, with a potential series of replies. 399 * Return -errno on error, 0 on success. */ 400 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) 401 { 402 NBDExport *exp; 403 assert(client->opt == NBD_OPT_LIST); 404 405 /* For each export, send a NBD_REP_SERVER reply. */ 406 QTAILQ_FOREACH(exp, &exports, next) { 407 if (nbd_negotiate_send_rep_list(client, exp, errp)) { 408 return -EINVAL; 409 } 410 } 411 /* Finish with a NBD_REP_ACK. */ 412 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 413 } 414 415 static void nbd_check_meta_export(NBDClient *client) 416 { 417 client->export_meta.valid &= client->exp == client->export_meta.exp; 418 } 419 420 /* Send a reply to NBD_OPT_EXPORT_NAME. 421 * Return -errno on error, 0 on success. */ 422 static int nbd_negotiate_handle_export_name(NBDClient *client, 423 uint16_t myflags, bool no_zeroes, 424 Error **errp) 425 { 426 char name[NBD_MAX_NAME_SIZE + 1]; 427 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 428 size_t len; 429 int ret; 430 431 /* Client sends: 432 [20 .. xx] export name (length bytes) 433 Server replies: 434 [ 0 .. 7] size 435 [ 8 .. 9] export flags 436 [10 .. 133] reserved (0) [unless no_zeroes] 437 */ 438 trace_nbd_negotiate_handle_export_name(); 439 if (client->optlen >= sizeof(name)) { 440 error_setg(errp, "Bad length received"); 441 return -EINVAL; 442 } 443 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) { 444 return -EIO; 445 } 446 name[client->optlen] = '\0'; 447 client->optlen = 0; 448 449 trace_nbd_negotiate_handle_export_name_request(name); 450 451 client->exp = nbd_export_find(name); 452 if (!client->exp) { 453 error_setg(errp, "export not found"); 454 return -EINVAL; 455 } 456 457 trace_nbd_negotiate_new_style_size_flags(client->exp->size, 458 client->exp->nbdflags | myflags); 459 stq_be_p(buf, client->exp->size); 460 stw_be_p(buf + 8, client->exp->nbdflags | myflags); 461 len = no_zeroes ? 10 : sizeof(buf); 462 ret = nbd_write(client->ioc, buf, len, errp); 463 if (ret < 0) { 464 error_prepend(errp, "write failed: "); 465 return ret; 466 } 467 468 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 469 nbd_export_get(client->exp); 470 nbd_check_meta_export(client); 471 472 return 0; 473 } 474 475 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 476 * The buffer does NOT include the info type prefix. 477 * Return -errno on error, 0 if ready to send more. */ 478 static int nbd_negotiate_send_info(NBDClient *client, 479 uint16_t info, uint32_t length, void *buf, 480 Error **errp) 481 { 482 int rc; 483 484 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 485 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 486 sizeof(info) + length, errp); 487 if (rc < 0) { 488 return rc; 489 } 490 info = cpu_to_be16(info); 491 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 492 return -EIO; 493 } 494 if (nbd_write(client->ioc, buf, length, errp) < 0) { 495 return -EIO; 496 } 497 return 0; 498 } 499 500 /* nbd_reject_length: Handle any unexpected payload. 501 * @fatal requests that we quit talking to the client, even if we are able 502 * to successfully send an error reply. 503 * Return: 504 * -errno transmission error occurred or @fatal was requested, errp is set 505 * 0 error message successfully sent to client, errp is not set 506 */ 507 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 508 { 509 int ret; 510 511 assert(client->optlen); 512 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length", 513 nbd_opt_lookup(client->opt)); 514 if (fatal && !ret) { 515 error_setg(errp, "option '%s' has unexpected length", 516 nbd_opt_lookup(client->opt)); 517 return -EINVAL; 518 } 519 return ret; 520 } 521 522 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 523 * Return -errno on error, 0 if ready for next option, and 1 to move 524 * into transmission phase. */ 525 static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags, 526 Error **errp) 527 { 528 int rc; 529 char name[NBD_MAX_NAME_SIZE + 1]; 530 NBDExport *exp; 531 uint16_t requests; 532 uint16_t request; 533 uint32_t namelen; 534 bool sendname = false; 535 bool blocksize = false; 536 uint32_t sizes[3]; 537 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 538 uint32_t check_align = 0; 539 540 /* Client sends: 541 4 bytes: L, name length (can be 0) 542 L bytes: export name 543 2 bytes: N, number of requests (can be 0) 544 N * 2 bytes: N requests 545 */ 546 rc = nbd_opt_read_name(client, name, &namelen, errp); 547 if (rc <= 0) { 548 return rc; 549 } 550 trace_nbd_negotiate_handle_export_name_request(name); 551 552 rc = nbd_opt_read(client, &requests, sizeof(requests), errp); 553 if (rc <= 0) { 554 return rc; 555 } 556 requests = be16_to_cpu(requests); 557 trace_nbd_negotiate_handle_info_requests(requests); 558 while (requests--) { 559 rc = nbd_opt_read(client, &request, sizeof(request), errp); 560 if (rc <= 0) { 561 return rc; 562 } 563 request = be16_to_cpu(request); 564 trace_nbd_negotiate_handle_info_request(request, 565 nbd_info_lookup(request)); 566 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 567 * everything else is either a request we don't know or 568 * something we send regardless of request */ 569 switch (request) { 570 case NBD_INFO_NAME: 571 sendname = true; 572 break; 573 case NBD_INFO_BLOCK_SIZE: 574 blocksize = true; 575 break; 576 } 577 } 578 if (client->optlen) { 579 return nbd_reject_length(client, false, errp); 580 } 581 582 exp = nbd_export_find(name); 583 if (!exp) { 584 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 585 errp, "export '%s' not present", 586 name); 587 } 588 589 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 590 if (sendname) { 591 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 592 errp); 593 if (rc < 0) { 594 return rc; 595 } 596 } 597 598 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 599 * client request */ 600 if (exp->description) { 601 size_t len = strlen(exp->description); 602 603 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 604 len, exp->description, errp); 605 if (rc < 0) { 606 return rc; 607 } 608 } 609 610 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 611 * according to whether the client requested it, and according to 612 * whether this is OPT_INFO or OPT_GO. */ 613 /* minimum - 1 for back-compat, or actual if client will obey it. */ 614 if (client->opt == NBD_OPT_INFO || blocksize) { 615 check_align = sizes[0] = blk_get_request_alignment(exp->blk); 616 } else { 617 sizes[0] = 1; 618 } 619 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE); 620 /* preferred - Hard-code to 4096 for now. 621 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 622 sizes[1] = MAX(4096, sizes[0]); 623 /* maximum - At most 32M, but smaller as appropriate. */ 624 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE); 625 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 626 sizes[0] = cpu_to_be32(sizes[0]); 627 sizes[1] = cpu_to_be32(sizes[1]); 628 sizes[2] = cpu_to_be32(sizes[2]); 629 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 630 sizeof(sizes), sizes, errp); 631 if (rc < 0) { 632 return rc; 633 } 634 635 /* Send NBD_INFO_EXPORT always */ 636 trace_nbd_negotiate_new_style_size_flags(exp->size, 637 exp->nbdflags | myflags); 638 stq_be_p(buf, exp->size); 639 stw_be_p(buf + 8, exp->nbdflags | myflags); 640 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 641 sizeof(buf), buf, errp); 642 if (rc < 0) { 643 return rc; 644 } 645 646 /* 647 * If the client is just asking for NBD_OPT_INFO, but forgot to 648 * request block sizes in a situation that would impact 649 * performance, then return an error. But for NBD_OPT_GO, we 650 * tolerate all clients, regardless of alignments. 651 */ 652 if (client->opt == NBD_OPT_INFO && !blocksize && 653 blk_get_request_alignment(exp->blk) > 1) { 654 return nbd_negotiate_send_rep_err(client, 655 NBD_REP_ERR_BLOCK_SIZE_REQD, 656 errp, 657 "request NBD_INFO_BLOCK_SIZE to " 658 "use this export"); 659 } 660 661 /* Final reply */ 662 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 663 if (rc < 0) { 664 return rc; 665 } 666 667 if (client->opt == NBD_OPT_GO) { 668 client->exp = exp; 669 client->check_align = check_align; 670 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 671 nbd_export_get(client->exp); 672 nbd_check_meta_export(client); 673 rc = 1; 674 } 675 return rc; 676 } 677 678 679 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 680 * new channel for all further (now-encrypted) communication. */ 681 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 682 Error **errp) 683 { 684 QIOChannel *ioc; 685 QIOChannelTLS *tioc; 686 struct NBDTLSHandshakeData data = { 0 }; 687 688 assert(client->opt == NBD_OPT_STARTTLS); 689 690 trace_nbd_negotiate_handle_starttls(); 691 ioc = client->ioc; 692 693 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 694 return NULL; 695 } 696 697 tioc = qio_channel_tls_new_server(ioc, 698 client->tlscreds, 699 client->tlsauthz, 700 errp); 701 if (!tioc) { 702 return NULL; 703 } 704 705 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 706 trace_nbd_negotiate_handle_starttls_handshake(); 707 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 708 qio_channel_tls_handshake(tioc, 709 nbd_tls_handshake, 710 &data, 711 NULL, 712 NULL); 713 714 if (!data.complete) { 715 g_main_loop_run(data.loop); 716 } 717 g_main_loop_unref(data.loop); 718 if (data.error) { 719 object_unref(OBJECT(tioc)); 720 error_propagate(errp, data.error); 721 return NULL; 722 } 723 724 return QIO_CHANNEL(tioc); 725 } 726 727 /* nbd_negotiate_send_meta_context 728 * 729 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT 730 * 731 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead. 732 */ 733 static int nbd_negotiate_send_meta_context(NBDClient *client, 734 const char *context, 735 uint32_t context_id, 736 Error **errp) 737 { 738 NBDOptionReplyMetaContext opt; 739 struct iovec iov[] = { 740 {.iov_base = &opt, .iov_len = sizeof(opt)}, 741 {.iov_base = (void *)context, .iov_len = strlen(context)} 742 }; 743 744 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 745 context_id = 0; 746 } 747 748 trace_nbd_negotiate_meta_query_reply(context, context_id); 749 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT, 750 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len); 751 stl_be_p(&opt.context_id, context_id); 752 753 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; 754 } 755 756 /* Read strlen(@pattern) bytes, and set @match to true if they match @pattern. 757 * @match is never set to false. 758 * 759 * Return -errno on I/O error, 0 if option was completely handled by 760 * sending a reply about inconsistent lengths, or 1 on success. 761 * 762 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 763 * It only means that there are no errors. 764 */ 765 static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match, 766 Error **errp) 767 { 768 int ret; 769 char *query; 770 size_t len = strlen(pattern); 771 772 assert(len); 773 774 query = g_malloc(len); 775 ret = nbd_opt_read(client, query, len, errp); 776 if (ret <= 0) { 777 g_free(query); 778 return ret; 779 } 780 781 if (strncmp(query, pattern, len) == 0) { 782 trace_nbd_negotiate_meta_query_parse(pattern); 783 *match = true; 784 } else { 785 trace_nbd_negotiate_meta_query_skip("pattern not matched"); 786 } 787 g_free(query); 788 789 return 1; 790 } 791 792 /* 793 * Read @len bytes, and set @match to true if they match @pattern, or if @len 794 * is 0 and the client is performing _LIST_. @match is never set to false. 795 * 796 * Return -errno on I/O error, 0 if option was completely handled by 797 * sending a reply about inconsistent lengths, or 1 on success. 798 * 799 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 800 * It only means that there are no errors. 801 */ 802 static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, 803 uint32_t len, bool *match, Error **errp) 804 { 805 if (len == 0) { 806 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 807 *match = true; 808 } 809 trace_nbd_negotiate_meta_query_parse("empty"); 810 return 1; 811 } 812 813 if (len != strlen(pattern)) { 814 trace_nbd_negotiate_meta_query_skip("different lengths"); 815 return nbd_opt_skip(client, len, errp); 816 } 817 818 return nbd_meta_pattern(client, pattern, match, errp); 819 } 820 821 /* nbd_meta_base_query 822 * 823 * Handle queries to 'base' namespace. For now, only the base:allocation 824 * context is available. 'len' is the amount of text remaining to be read from 825 * the current name, after the 'base:' portion has been stripped. 826 * 827 * Return -errno on I/O error, 0 if option was completely handled by 828 * sending a reply about inconsistent lengths, or 1 on success. 829 */ 830 static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta, 831 uint32_t len, Error **errp) 832 { 833 return nbd_meta_empty_or_pattern(client, "allocation", len, 834 &meta->base_allocation, errp); 835 } 836 837 /* nbd_meta_bitmap_query 838 * 839 * Handle query to 'qemu:' namespace. 840 * @len is the amount of text remaining to be read from the current name, after 841 * the 'qemu:' portion has been stripped. 842 * 843 * Return -errno on I/O error, 0 if option was completely handled by 844 * sending a reply about inconsistent lengths, or 1 on success. */ 845 static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta, 846 uint32_t len, Error **errp) 847 { 848 bool dirty_bitmap = false; 849 size_t dirty_bitmap_len = strlen("dirty-bitmap:"); 850 int ret; 851 852 if (!meta->exp->export_bitmap) { 853 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported"); 854 return nbd_opt_skip(client, len, errp); 855 } 856 857 if (len == 0) { 858 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 859 meta->bitmap = true; 860 } 861 trace_nbd_negotiate_meta_query_parse("empty"); 862 return 1; 863 } 864 865 if (len < dirty_bitmap_len) { 866 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 867 return nbd_opt_skip(client, len, errp); 868 } 869 870 len -= dirty_bitmap_len; 871 ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp); 872 if (ret <= 0) { 873 return ret; 874 } 875 if (!dirty_bitmap) { 876 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 877 return nbd_opt_skip(client, len, errp); 878 } 879 880 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); 881 882 return nbd_meta_empty_or_pattern( 883 client, meta->exp->export_bitmap_context + 884 strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp); 885 } 886 887 /* nbd_negotiate_meta_query 888 * 889 * Parse namespace name and call corresponding function to parse body of the 890 * query. 891 * 892 * The only supported namespace now is 'base'. 893 * 894 * The function aims not wasting time and memory to read long unknown namespace 895 * names. 896 * 897 * Return -errno on I/O error, 0 if option was completely handled by 898 * sending a reply about inconsistent lengths, or 1 on success. */ 899 static int nbd_negotiate_meta_query(NBDClient *client, 900 NBDExportMetaContexts *meta, Error **errp) 901 { 902 /* 903 * Both 'qemu' and 'base' namespaces have length = 5 including a 904 * colon. If another length namespace is later introduced, this 905 * should certainly be refactored. 906 */ 907 int ret; 908 size_t ns_len = 5; 909 char ns[5]; 910 uint32_t len; 911 912 ret = nbd_opt_read(client, &len, sizeof(len), errp); 913 if (ret <= 0) { 914 return ret; 915 } 916 len = cpu_to_be32(len); 917 918 if (len < ns_len) { 919 trace_nbd_negotiate_meta_query_skip("length too short"); 920 return nbd_opt_skip(client, len, errp); 921 } 922 923 len -= ns_len; 924 ret = nbd_opt_read(client, ns, ns_len, errp); 925 if (ret <= 0) { 926 return ret; 927 } 928 929 if (!strncmp(ns, "base:", ns_len)) { 930 trace_nbd_negotiate_meta_query_parse("base:"); 931 return nbd_meta_base_query(client, meta, len, errp); 932 } else if (!strncmp(ns, "qemu:", ns_len)) { 933 trace_nbd_negotiate_meta_query_parse("qemu:"); 934 return nbd_meta_qemu_query(client, meta, len, errp); 935 } 936 937 trace_nbd_negotiate_meta_query_skip("unknown namespace"); 938 return nbd_opt_skip(client, len, errp); 939 } 940 941 /* nbd_negotiate_meta_queries 942 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT 943 * 944 * Return -errno on I/O error, or 0 if option was completely handled. */ 945 static int nbd_negotiate_meta_queries(NBDClient *client, 946 NBDExportMetaContexts *meta, Error **errp) 947 { 948 int ret; 949 char export_name[NBD_MAX_NAME_SIZE + 1]; 950 NBDExportMetaContexts local_meta; 951 uint32_t nb_queries; 952 int i; 953 954 if (!client->structured_reply) { 955 return nbd_opt_invalid(client, errp, 956 "request option '%s' when structured reply " 957 "is not negotiated", 958 nbd_opt_lookup(client->opt)); 959 } 960 961 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 962 /* Only change the caller's meta on SET. */ 963 meta = &local_meta; 964 } 965 966 memset(meta, 0, sizeof(*meta)); 967 968 ret = nbd_opt_read_name(client, export_name, NULL, errp); 969 if (ret <= 0) { 970 return ret; 971 } 972 973 meta->exp = nbd_export_find(export_name); 974 if (meta->exp == NULL) { 975 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, 976 "export '%s' not present", export_name); 977 } 978 979 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp); 980 if (ret <= 0) { 981 return ret; 982 } 983 nb_queries = cpu_to_be32(nb_queries); 984 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), 985 export_name, nb_queries); 986 987 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { 988 /* enable all known contexts */ 989 meta->base_allocation = true; 990 meta->bitmap = !!meta->exp->export_bitmap; 991 } else { 992 for (i = 0; i < nb_queries; ++i) { 993 ret = nbd_negotiate_meta_query(client, meta, errp); 994 if (ret <= 0) { 995 return ret; 996 } 997 } 998 } 999 1000 if (meta->base_allocation) { 1001 ret = nbd_negotiate_send_meta_context(client, "base:allocation", 1002 NBD_META_ID_BASE_ALLOCATION, 1003 errp); 1004 if (ret < 0) { 1005 return ret; 1006 } 1007 } 1008 1009 if (meta->bitmap) { 1010 ret = nbd_negotiate_send_meta_context(client, 1011 meta->exp->export_bitmap_context, 1012 NBD_META_ID_DIRTY_BITMAP, 1013 errp); 1014 if (ret < 0) { 1015 return ret; 1016 } 1017 } 1018 1019 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1020 if (ret == 0) { 1021 meta->valid = true; 1022 } 1023 1024 return ret; 1025 } 1026 1027 /* nbd_negotiate_options 1028 * Process all NBD_OPT_* client option commands, during fixed newstyle 1029 * negotiation. 1030 * Return: 1031 * -errno on error, errp is set 1032 * 0 on successful negotiation, errp is not set 1033 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1034 * errp is not set 1035 */ 1036 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags, 1037 Error **errp) 1038 { 1039 uint32_t flags; 1040 bool fixedNewstyle = false; 1041 bool no_zeroes = false; 1042 1043 /* Client sends: 1044 [ 0 .. 3] client flags 1045 1046 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 1047 [ 0 .. 7] NBD_OPTS_MAGIC 1048 [ 8 .. 11] NBD option 1049 [12 .. 15] Data length 1050 ... Rest of request 1051 1052 [ 0 .. 7] NBD_OPTS_MAGIC 1053 [ 8 .. 11] Second NBD option 1054 [12 .. 15] Data length 1055 ... Rest of request 1056 */ 1057 1058 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) { 1059 return -EIO; 1060 } 1061 trace_nbd_negotiate_options_flags(flags); 1062 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1063 fixedNewstyle = true; 1064 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1065 } 1066 if (flags & NBD_FLAG_C_NO_ZEROES) { 1067 no_zeroes = true; 1068 flags &= ~NBD_FLAG_C_NO_ZEROES; 1069 } 1070 if (flags != 0) { 1071 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1072 return -EINVAL; 1073 } 1074 1075 while (1) { 1076 int ret; 1077 uint32_t option, length; 1078 uint64_t magic; 1079 1080 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) { 1081 return -EINVAL; 1082 } 1083 trace_nbd_negotiate_options_check_magic(magic); 1084 if (magic != NBD_OPTS_MAGIC) { 1085 error_setg(errp, "Bad magic received"); 1086 return -EINVAL; 1087 } 1088 1089 if (nbd_read32(client->ioc, &option, "option", errp) < 0) { 1090 return -EINVAL; 1091 } 1092 client->opt = option; 1093 1094 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) { 1095 return -EINVAL; 1096 } 1097 assert(!client->optlen); 1098 client->optlen = length; 1099 1100 if (length > NBD_MAX_BUFFER_SIZE) { 1101 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1102 length, NBD_MAX_BUFFER_SIZE); 1103 return -EINVAL; 1104 } 1105 1106 trace_nbd_negotiate_options_check_option(option, 1107 nbd_opt_lookup(option)); 1108 if (client->tlscreds && 1109 client->ioc == (QIOChannel *)client->sioc) { 1110 QIOChannel *tioc; 1111 if (!fixedNewstyle) { 1112 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1113 return -EINVAL; 1114 } 1115 switch (option) { 1116 case NBD_OPT_STARTTLS: 1117 if (length) { 1118 /* Unconditionally drop the connection if the client 1119 * can't start a TLS negotiation correctly */ 1120 return nbd_reject_length(client, true, errp); 1121 } 1122 tioc = nbd_negotiate_handle_starttls(client, errp); 1123 if (!tioc) { 1124 return -EIO; 1125 } 1126 ret = 0; 1127 object_unref(OBJECT(client->ioc)); 1128 client->ioc = QIO_CHANNEL(tioc); 1129 break; 1130 1131 case NBD_OPT_EXPORT_NAME: 1132 /* No way to return an error to client, so drop connection */ 1133 error_setg(errp, "Option 0x%x not permitted before TLS", 1134 option); 1135 return -EINVAL; 1136 1137 default: 1138 /* Let the client keep trying, unless they asked to 1139 * quit. Always try to give an error back to the 1140 * client; but when replying to OPT_ABORT, be aware 1141 * that the client may hang up before receiving the 1142 * error, in which case we are fine ignoring the 1143 * resulting EPIPE. */ 1144 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, 1145 option == NBD_OPT_ABORT ? NULL : errp, 1146 "Option 0x%" PRIx32 1147 " not permitted before TLS", option); 1148 if (option == NBD_OPT_ABORT) { 1149 return 1; 1150 } 1151 break; 1152 } 1153 } else if (fixedNewstyle) { 1154 switch (option) { 1155 case NBD_OPT_LIST: 1156 if (length) { 1157 ret = nbd_reject_length(client, false, errp); 1158 } else { 1159 ret = nbd_negotiate_handle_list(client, errp); 1160 } 1161 break; 1162 1163 case NBD_OPT_ABORT: 1164 /* NBD spec says we must try to reply before 1165 * disconnecting, but that we must also tolerate 1166 * guests that don't wait for our reply. */ 1167 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1168 return 1; 1169 1170 case NBD_OPT_EXPORT_NAME: 1171 return nbd_negotiate_handle_export_name(client, 1172 myflags, no_zeroes, 1173 errp); 1174 1175 case NBD_OPT_INFO: 1176 case NBD_OPT_GO: 1177 ret = nbd_negotiate_handle_info(client, myflags, errp); 1178 if (ret == 1) { 1179 assert(option == NBD_OPT_GO); 1180 return 0; 1181 } 1182 break; 1183 1184 case NBD_OPT_STARTTLS: 1185 if (length) { 1186 ret = nbd_reject_length(client, false, errp); 1187 } else if (client->tlscreds) { 1188 ret = nbd_negotiate_send_rep_err(client, 1189 NBD_REP_ERR_INVALID, errp, 1190 "TLS already enabled"); 1191 } else { 1192 ret = nbd_negotiate_send_rep_err(client, 1193 NBD_REP_ERR_POLICY, errp, 1194 "TLS not configured"); 1195 } 1196 break; 1197 1198 case NBD_OPT_STRUCTURED_REPLY: 1199 if (length) { 1200 ret = nbd_reject_length(client, false, errp); 1201 } else if (client->structured_reply) { 1202 ret = nbd_negotiate_send_rep_err( 1203 client, NBD_REP_ERR_INVALID, errp, 1204 "structured reply already negotiated"); 1205 } else { 1206 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1207 client->structured_reply = true; 1208 myflags |= NBD_FLAG_SEND_DF; 1209 } 1210 break; 1211 1212 case NBD_OPT_LIST_META_CONTEXT: 1213 case NBD_OPT_SET_META_CONTEXT: 1214 ret = nbd_negotiate_meta_queries(client, &client->export_meta, 1215 errp); 1216 break; 1217 1218 default: 1219 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1220 "Unsupported option %" PRIu32 " (%s)", 1221 option, nbd_opt_lookup(option)); 1222 break; 1223 } 1224 } else { 1225 /* 1226 * If broken new-style we should drop the connection 1227 * for anything except NBD_OPT_EXPORT_NAME 1228 */ 1229 switch (option) { 1230 case NBD_OPT_EXPORT_NAME: 1231 return nbd_negotiate_handle_export_name(client, 1232 myflags, no_zeroes, 1233 errp); 1234 1235 default: 1236 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1237 option, nbd_opt_lookup(option)); 1238 return -EINVAL; 1239 } 1240 } 1241 if (ret < 0) { 1242 return ret; 1243 } 1244 } 1245 } 1246 1247 /* nbd_negotiate 1248 * Return: 1249 * -errno on error, errp is set 1250 * 0 on successful negotiation, errp is not set 1251 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1252 * errp is not set 1253 */ 1254 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1255 { 1256 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1257 int ret; 1258 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | 1259 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA | 1260 NBD_FLAG_SEND_WRITE_ZEROES | NBD_FLAG_SEND_CACHE); 1261 1262 /* Old style negotiation header, no room for options 1263 [ 0 .. 7] passwd ("NBDMAGIC") 1264 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1265 [16 .. 23] size 1266 [24 .. 27] export flags (zero-extended) 1267 [28 .. 151] reserved (0) 1268 1269 New style negotiation header, client can send options 1270 [ 0 .. 7] passwd ("NBDMAGIC") 1271 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1272 [16 .. 17] server flags (0) 1273 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1274 */ 1275 1276 qio_channel_set_blocking(client->ioc, false, NULL); 1277 1278 trace_nbd_negotiate_begin(); 1279 memcpy(buf, "NBDMAGIC", 8); 1280 1281 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1282 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1283 1284 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 1285 error_prepend(errp, "write failed: "); 1286 return -EINVAL; 1287 } 1288 ret = nbd_negotiate_options(client, myflags, errp); 1289 if (ret != 0) { 1290 if (ret < 0) { 1291 error_prepend(errp, "option negotiation failed: "); 1292 } 1293 return ret; 1294 } 1295 1296 assert(!client->optlen); 1297 trace_nbd_negotiate_success(); 1298 1299 return 0; 1300 } 1301 1302 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 1303 Error **errp) 1304 { 1305 uint8_t buf[NBD_REQUEST_SIZE]; 1306 uint32_t magic; 1307 int ret; 1308 1309 ret = nbd_read(ioc, buf, sizeof(buf), "request", errp); 1310 if (ret < 0) { 1311 return ret; 1312 } 1313 1314 /* Request 1315 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1316 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1317 [ 6 .. 7] type (NBD_CMD_READ, ...) 1318 [ 8 .. 15] handle 1319 [16 .. 23] from 1320 [24 .. 27] len 1321 */ 1322 1323 magic = ldl_be_p(buf); 1324 request->flags = lduw_be_p(buf + 4); 1325 request->type = lduw_be_p(buf + 6); 1326 request->handle = ldq_be_p(buf + 8); 1327 request->from = ldq_be_p(buf + 16); 1328 request->len = ldl_be_p(buf + 24); 1329 1330 trace_nbd_receive_request(magic, request->flags, request->type, 1331 request->from, request->len); 1332 1333 if (magic != NBD_REQUEST_MAGIC) { 1334 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 1335 return -EINVAL; 1336 } 1337 return 0; 1338 } 1339 1340 #define MAX_NBD_REQUESTS 16 1341 1342 void nbd_client_get(NBDClient *client) 1343 { 1344 client->refcount++; 1345 } 1346 1347 void nbd_client_put(NBDClient *client) 1348 { 1349 if (--client->refcount == 0) { 1350 /* The last reference should be dropped by client->close, 1351 * which is called by client_close. 1352 */ 1353 assert(client->closing); 1354 1355 qio_channel_detach_aio_context(client->ioc); 1356 object_unref(OBJECT(client->sioc)); 1357 object_unref(OBJECT(client->ioc)); 1358 if (client->tlscreds) { 1359 object_unref(OBJECT(client->tlscreds)); 1360 } 1361 g_free(client->tlsauthz); 1362 if (client->exp) { 1363 QTAILQ_REMOVE(&client->exp->clients, client, next); 1364 nbd_export_put(client->exp); 1365 } 1366 g_free(client); 1367 } 1368 } 1369 1370 static void client_close(NBDClient *client, bool negotiated) 1371 { 1372 if (client->closing) { 1373 return; 1374 } 1375 1376 client->closing = true; 1377 1378 /* Force requests to finish. They will drop their own references, 1379 * then we'll close the socket and free the NBDClient. 1380 */ 1381 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1382 NULL); 1383 1384 /* Also tell the client, so that they release their reference. */ 1385 if (client->close_fn) { 1386 client->close_fn(client, negotiated); 1387 } 1388 } 1389 1390 static NBDRequestData *nbd_request_get(NBDClient *client) 1391 { 1392 NBDRequestData *req; 1393 1394 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1395 client->nb_requests++; 1396 1397 req = g_new0(NBDRequestData, 1); 1398 nbd_client_get(client); 1399 req->client = client; 1400 return req; 1401 } 1402 1403 static void nbd_request_put(NBDRequestData *req) 1404 { 1405 NBDClient *client = req->client; 1406 1407 if (req->data) { 1408 qemu_vfree(req->data); 1409 } 1410 g_free(req); 1411 1412 client->nb_requests--; 1413 nbd_client_receive_next_request(client); 1414 1415 nbd_client_put(client); 1416 } 1417 1418 static void blk_aio_attached(AioContext *ctx, void *opaque) 1419 { 1420 NBDExport *exp = opaque; 1421 NBDClient *client; 1422 1423 trace_nbd_blk_aio_attached(exp->name, ctx); 1424 1425 exp->ctx = ctx; 1426 1427 QTAILQ_FOREACH(client, &exp->clients, next) { 1428 qio_channel_attach_aio_context(client->ioc, ctx); 1429 if (client->recv_coroutine) { 1430 aio_co_schedule(ctx, client->recv_coroutine); 1431 } 1432 if (client->send_coroutine) { 1433 aio_co_schedule(ctx, client->send_coroutine); 1434 } 1435 } 1436 } 1437 1438 static void blk_aio_detach(void *opaque) 1439 { 1440 NBDExport *exp = opaque; 1441 NBDClient *client; 1442 1443 trace_nbd_blk_aio_detach(exp->name, exp->ctx); 1444 1445 QTAILQ_FOREACH(client, &exp->clients, next) { 1446 qio_channel_detach_aio_context(client->ioc); 1447 } 1448 1449 exp->ctx = NULL; 1450 } 1451 1452 static void nbd_eject_notifier(Notifier *n, void *data) 1453 { 1454 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1455 nbd_export_close(exp); 1456 } 1457 1458 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset, 1459 uint64_t size, const char *name, const char *desc, 1460 const char *bitmap, uint16_t nbdflags, 1461 void (*close)(NBDExport *), bool writethrough, 1462 BlockBackend *on_eject_blk, Error **errp) 1463 { 1464 AioContext *ctx; 1465 BlockBackend *blk; 1466 NBDExport *exp = g_new0(NBDExport, 1); 1467 uint64_t perm; 1468 int ret; 1469 1470 /* 1471 * NBD exports are used for non-shared storage migration. Make sure 1472 * that BDRV_O_INACTIVE is cleared and the image is ready for write 1473 * access since the export could be available before migration handover. 1474 */ 1475 assert(name); 1476 ctx = bdrv_get_aio_context(bs); 1477 aio_context_acquire(ctx); 1478 bdrv_invalidate_cache(bs, NULL); 1479 aio_context_release(ctx); 1480 1481 /* Don't allow resize while the NBD server is running, otherwise we don't 1482 * care what happens with the node. */ 1483 perm = BLK_PERM_CONSISTENT_READ; 1484 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) { 1485 perm |= BLK_PERM_WRITE; 1486 } 1487 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1488 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); 1489 ret = blk_insert_bs(blk, bs, errp); 1490 if (ret < 0) { 1491 goto fail; 1492 } 1493 blk_set_enable_write_cache(blk, !writethrough); 1494 1495 exp->refcount = 1; 1496 QTAILQ_INIT(&exp->clients); 1497 exp->blk = blk; 1498 assert(dev_offset <= INT64_MAX); 1499 exp->dev_offset = dev_offset; 1500 exp->name = g_strdup(name); 1501 exp->description = g_strdup(desc); 1502 exp->nbdflags = nbdflags; 1503 assert(size <= INT64_MAX - dev_offset); 1504 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); 1505 1506 if (bitmap) { 1507 BdrvDirtyBitmap *bm = NULL; 1508 1509 while (true) { 1510 bm = bdrv_find_dirty_bitmap(bs, bitmap); 1511 if (bm != NULL || bs->backing == NULL) { 1512 break; 1513 } 1514 1515 bs = bs->backing->bs; 1516 } 1517 1518 if (bm == NULL) { 1519 error_setg(errp, "Bitmap '%s' is not found", bitmap); 1520 goto fail; 1521 } 1522 1523 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) { 1524 goto fail; 1525 } 1526 1527 if ((nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) && 1528 bdrv_dirty_bitmap_enabled(bm)) { 1529 error_setg(errp, 1530 "Enabled bitmap '%s' incompatible with readonly export", 1531 bitmap); 1532 goto fail; 1533 } 1534 1535 bdrv_dirty_bitmap_set_busy(bm, true); 1536 exp->export_bitmap = bm; 1537 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s", 1538 bitmap); 1539 } 1540 1541 exp->close = close; 1542 exp->ctx = blk_get_aio_context(blk); 1543 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1544 1545 if (on_eject_blk) { 1546 blk_ref(on_eject_blk); 1547 exp->eject_notifier_blk = on_eject_blk; 1548 exp->eject_notifier.notify = nbd_eject_notifier; 1549 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier); 1550 } 1551 QTAILQ_INSERT_TAIL(&exports, exp, next); 1552 nbd_export_get(exp); 1553 return exp; 1554 1555 fail: 1556 blk_unref(blk); 1557 g_free(exp->name); 1558 g_free(exp->description); 1559 g_free(exp); 1560 return NULL; 1561 } 1562 1563 NBDExport *nbd_export_find(const char *name) 1564 { 1565 NBDExport *exp; 1566 QTAILQ_FOREACH(exp, &exports, next) { 1567 if (strcmp(name, exp->name) == 0) { 1568 return exp; 1569 } 1570 } 1571 1572 return NULL; 1573 } 1574 1575 void nbd_export_close(NBDExport *exp) 1576 { 1577 NBDClient *client, *next; 1578 1579 nbd_export_get(exp); 1580 /* 1581 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a 1582 * close mode that stops advertising the export to new clients but 1583 * still permits existing clients to run to completion? Because of 1584 * that possibility, nbd_export_close() can be called more than 1585 * once on an export. 1586 */ 1587 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1588 client_close(client, true); 1589 } 1590 if (exp->name) { 1591 nbd_export_put(exp); 1592 g_free(exp->name); 1593 exp->name = NULL; 1594 QTAILQ_REMOVE(&exports, exp, next); 1595 } 1596 g_free(exp->description); 1597 exp->description = NULL; 1598 nbd_export_put(exp); 1599 } 1600 1601 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp) 1602 { 1603 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) { 1604 nbd_export_close(exp); 1605 return; 1606 } 1607 1608 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE); 1609 1610 error_setg(errp, "export '%s' still in use", exp->name); 1611 error_append_hint(errp, "Use mode='hard' to force client disconnect\n"); 1612 } 1613 1614 void nbd_export_get(NBDExport *exp) 1615 { 1616 assert(exp->refcount > 0); 1617 exp->refcount++; 1618 } 1619 1620 void nbd_export_put(NBDExport *exp) 1621 { 1622 assert(exp->refcount > 0); 1623 if (exp->refcount == 1) { 1624 nbd_export_close(exp); 1625 } 1626 1627 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen 1628 * if someone calls nbd_export_put() on named export not through 1629 * nbd_export_set_name() when refcount is 1. So, let's assert that 1630 * it is > 0. 1631 */ 1632 assert(exp->refcount > 0); 1633 if (--exp->refcount == 0) { 1634 assert(exp->name == NULL); 1635 assert(exp->description == NULL); 1636 1637 if (exp->close) { 1638 exp->close(exp); 1639 } 1640 1641 if (exp->blk) { 1642 if (exp->eject_notifier_blk) { 1643 notifier_remove(&exp->eject_notifier); 1644 blk_unref(exp->eject_notifier_blk); 1645 } 1646 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, 1647 blk_aio_detach, exp); 1648 blk_unref(exp->blk); 1649 exp->blk = NULL; 1650 } 1651 1652 if (exp->export_bitmap) { 1653 bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false); 1654 g_free(exp->export_bitmap_context); 1655 } 1656 1657 g_free(exp); 1658 } 1659 } 1660 1661 BlockBackend *nbd_export_get_blockdev(NBDExport *exp) 1662 { 1663 return exp->blk; 1664 } 1665 1666 void nbd_export_close_all(void) 1667 { 1668 NBDExport *exp, *next; 1669 1670 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { 1671 nbd_export_close(exp); 1672 } 1673 } 1674 1675 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1676 unsigned niov, Error **errp) 1677 { 1678 int ret; 1679 1680 g_assert(qemu_in_coroutine()); 1681 qemu_co_mutex_lock(&client->send_lock); 1682 client->send_coroutine = qemu_coroutine_self(); 1683 1684 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1685 1686 client->send_coroutine = NULL; 1687 qemu_co_mutex_unlock(&client->send_lock); 1688 1689 return ret; 1690 } 1691 1692 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1693 uint64_t handle) 1694 { 1695 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1696 stl_be_p(&reply->error, error); 1697 stq_be_p(&reply->handle, handle); 1698 } 1699 1700 static int nbd_co_send_simple_reply(NBDClient *client, 1701 uint64_t handle, 1702 uint32_t error, 1703 void *data, 1704 size_t len, 1705 Error **errp) 1706 { 1707 NBDSimpleReply reply; 1708 int nbd_err = system_errno_to_nbd_errno(error); 1709 struct iovec iov[] = { 1710 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1711 {.iov_base = data, .iov_len = len} 1712 }; 1713 1714 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1715 len); 1716 set_be_simple_reply(&reply, nbd_err, handle); 1717 1718 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1719 } 1720 1721 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1722 uint16_t type, uint64_t handle, uint32_t length) 1723 { 1724 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1725 stw_be_p(&chunk->flags, flags); 1726 stw_be_p(&chunk->type, type); 1727 stq_be_p(&chunk->handle, handle); 1728 stl_be_p(&chunk->length, length); 1729 } 1730 1731 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1732 uint64_t handle, 1733 Error **errp) 1734 { 1735 NBDStructuredReplyChunk chunk; 1736 struct iovec iov[] = { 1737 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1738 }; 1739 1740 trace_nbd_co_send_structured_done(handle); 1741 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1742 1743 return nbd_co_send_iov(client, iov, 1, errp); 1744 } 1745 1746 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1747 uint64_t handle, 1748 uint64_t offset, 1749 void *data, 1750 size_t size, 1751 bool final, 1752 Error **errp) 1753 { 1754 NBDStructuredReadData chunk; 1755 struct iovec iov[] = { 1756 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1757 {.iov_base = data, .iov_len = size} 1758 }; 1759 1760 assert(size); 1761 trace_nbd_co_send_structured_read(handle, offset, data, size); 1762 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1763 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1764 sizeof(chunk) - sizeof(chunk.h) + size); 1765 stq_be_p(&chunk.offset, offset); 1766 1767 return nbd_co_send_iov(client, iov, 2, errp); 1768 } 1769 1770 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1771 uint64_t handle, 1772 uint32_t error, 1773 const char *msg, 1774 Error **errp) 1775 { 1776 NBDStructuredError chunk; 1777 int nbd_err = system_errno_to_nbd_errno(error); 1778 struct iovec iov[] = { 1779 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1780 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1781 }; 1782 1783 assert(nbd_err); 1784 trace_nbd_co_send_structured_error(handle, nbd_err, 1785 nbd_err_lookup(nbd_err), msg ? msg : ""); 1786 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1787 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1788 stl_be_p(&chunk.error, nbd_err); 1789 stw_be_p(&chunk.message_length, iov[1].iov_len); 1790 1791 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1792 } 1793 1794 /* Do a sparse read and send the structured reply to the client. 1795 * Returns -errno if sending fails. bdrv_block_status_above() failure is 1796 * reported to the client, at which point this function succeeds. 1797 */ 1798 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1799 uint64_t handle, 1800 uint64_t offset, 1801 uint8_t *data, 1802 size_t size, 1803 Error **errp) 1804 { 1805 int ret = 0; 1806 NBDExport *exp = client->exp; 1807 size_t progress = 0; 1808 1809 while (progress < size) { 1810 int64_t pnum; 1811 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL, 1812 offset + progress, 1813 size - progress, &pnum, NULL, 1814 NULL); 1815 bool final; 1816 1817 if (status < 0) { 1818 char *msg = g_strdup_printf("unable to check for holes: %s", 1819 strerror(-status)); 1820 1821 ret = nbd_co_send_structured_error(client, handle, -status, msg, 1822 errp); 1823 g_free(msg); 1824 return ret; 1825 } 1826 assert(pnum && pnum <= size - progress); 1827 final = progress + pnum == size; 1828 if (status & BDRV_BLOCK_ZERO) { 1829 NBDStructuredReadHole chunk; 1830 struct iovec iov[] = { 1831 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1832 }; 1833 1834 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1835 pnum); 1836 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1837 NBD_REPLY_TYPE_OFFSET_HOLE, 1838 handle, sizeof(chunk) - sizeof(chunk.h)); 1839 stq_be_p(&chunk.offset, offset + progress); 1840 stl_be_p(&chunk.length, pnum); 1841 ret = nbd_co_send_iov(client, iov, 1, errp); 1842 } else { 1843 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset, 1844 data + progress, pnum); 1845 if (ret < 0) { 1846 error_setg_errno(errp, -ret, "reading from file failed"); 1847 break; 1848 } 1849 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1850 data + progress, pnum, final, 1851 errp); 1852 } 1853 1854 if (ret < 0) { 1855 break; 1856 } 1857 progress += pnum; 1858 } 1859 return ret; 1860 } 1861 1862 /* 1863 * Populate @extents from block status. Update @bytes to be the actual 1864 * length encoded (which may be smaller than the original), and update 1865 * @nb_extents to the number of extents used. 1866 * 1867 * Returns zero on success and -errno on bdrv_block_status_above failure. 1868 */ 1869 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, 1870 uint64_t *bytes, NBDExtent *extents, 1871 unsigned int *nb_extents) 1872 { 1873 uint64_t remaining_bytes = *bytes; 1874 NBDExtent *extent = extents, *extents_end = extents + *nb_extents; 1875 bool first_extent = true; 1876 1877 assert(*nb_extents); 1878 while (remaining_bytes) { 1879 uint32_t flags; 1880 int64_t num; 1881 int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes, 1882 &num, NULL, NULL); 1883 1884 if (ret < 0) { 1885 return ret; 1886 } 1887 1888 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) | 1889 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 1890 1891 if (first_extent) { 1892 extent->flags = flags; 1893 extent->length = num; 1894 first_extent = false; 1895 } else if (flags == extent->flags) { 1896 /* extend current extent */ 1897 extent->length += num; 1898 } else { 1899 if (extent + 1 == extents_end) { 1900 break; 1901 } 1902 1903 /* start new extent */ 1904 extent++; 1905 extent->flags = flags; 1906 extent->length = num; 1907 } 1908 offset += num; 1909 remaining_bytes -= num; 1910 } 1911 1912 extents_end = extent + 1; 1913 1914 for (extent = extents; extent < extents_end; extent++) { 1915 extent->flags = cpu_to_be32(extent->flags); 1916 extent->length = cpu_to_be32(extent->length); 1917 } 1918 1919 *bytes -= remaining_bytes; 1920 *nb_extents = extents_end - extents; 1921 1922 return 0; 1923 } 1924 1925 /* nbd_co_send_extents 1926 * 1927 * @length is only for tracing purposes (and may be smaller or larger 1928 * than the client's original request). @last controls whether 1929 * NBD_REPLY_FLAG_DONE is sent. @extents should already be in 1930 * big-endian format. 1931 */ 1932 static int nbd_co_send_extents(NBDClient *client, uint64_t handle, 1933 NBDExtent *extents, unsigned int nb_extents, 1934 uint64_t length, bool last, 1935 uint32_t context_id, Error **errp) 1936 { 1937 NBDStructuredMeta chunk; 1938 1939 struct iovec iov[] = { 1940 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1941 {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])} 1942 }; 1943 1944 trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last); 1945 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0, 1946 NBD_REPLY_TYPE_BLOCK_STATUS, 1947 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1948 stl_be_p(&chunk.context_id, context_id); 1949 1950 return nbd_co_send_iov(client, iov, 2, errp); 1951 } 1952 1953 /* Get block status from the exported device and send it to the client */ 1954 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, 1955 BlockDriverState *bs, uint64_t offset, 1956 uint32_t length, bool dont_fragment, 1957 bool last, uint32_t context_id, 1958 Error **errp) 1959 { 1960 int ret; 1961 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; 1962 NBDExtent *extents = g_new(NBDExtent, nb_extents); 1963 uint64_t final_length = length; 1964 1965 ret = blockstatus_to_extents(bs, offset, &final_length, extents, 1966 &nb_extents); 1967 if (ret < 0) { 1968 g_free(extents); 1969 return nbd_co_send_structured_error( 1970 client, handle, -ret, "can't get block status", errp); 1971 } 1972 1973 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 1974 final_length, last, context_id, errp); 1975 1976 g_free(extents); 1977 1978 return ret; 1979 } 1980 1981 /* 1982 * Populate @extents from a dirty bitmap. Unless @dont_fragment, the 1983 * final extent may exceed the original @length. Store in @length the 1984 * byte length encoded (which may be smaller or larger than the 1985 * original), and return the number of extents used. 1986 */ 1987 static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset, 1988 uint64_t *length, NBDExtent *extents, 1989 unsigned int nb_extents, 1990 bool dont_fragment) 1991 { 1992 uint64_t begin = offset, end = offset; 1993 uint64_t overall_end = offset + *length; 1994 unsigned int i = 0; 1995 BdrvDirtyBitmapIter *it; 1996 bool dirty; 1997 1998 bdrv_dirty_bitmap_lock(bitmap); 1999 2000 it = bdrv_dirty_iter_new(bitmap); 2001 dirty = bdrv_get_dirty_locked(NULL, bitmap, offset); 2002 2003 assert(begin < overall_end && nb_extents); 2004 while (begin < overall_end && i < nb_extents) { 2005 bool next_dirty = !dirty; 2006 2007 if (dirty) { 2008 end = bdrv_dirty_bitmap_next_zero(bitmap, begin, UINT64_MAX); 2009 } else { 2010 bdrv_set_dirty_iter(it, begin); 2011 end = bdrv_dirty_iter_next(it); 2012 } 2013 if (end == -1 || end - begin > UINT32_MAX) { 2014 /* Cap to an aligned value < 4G beyond begin. */ 2015 end = MIN(bdrv_dirty_bitmap_size(bitmap), 2016 begin + UINT32_MAX + 1 - 2017 bdrv_dirty_bitmap_granularity(bitmap)); 2018 next_dirty = dirty; 2019 } 2020 if (dont_fragment && end > overall_end) { 2021 end = overall_end; 2022 } 2023 2024 extents[i].length = cpu_to_be32(end - begin); 2025 extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0); 2026 i++; 2027 begin = end; 2028 dirty = next_dirty; 2029 } 2030 2031 bdrv_dirty_iter_free(it); 2032 2033 bdrv_dirty_bitmap_unlock(bitmap); 2034 2035 assert(offset < end); 2036 *length = end - offset; 2037 return i; 2038 } 2039 2040 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, 2041 BdrvDirtyBitmap *bitmap, uint64_t offset, 2042 uint32_t length, bool dont_fragment, bool last, 2043 uint32_t context_id, Error **errp) 2044 { 2045 int ret; 2046 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; 2047 NBDExtent *extents = g_new(NBDExtent, nb_extents); 2048 uint64_t final_length = length; 2049 2050 nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents, 2051 nb_extents, dont_fragment); 2052 2053 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 2054 final_length, last, context_id, errp); 2055 2056 g_free(extents); 2057 2058 return ret; 2059 } 2060 2061 /* nbd_co_receive_request 2062 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2063 * connection right away, and any other negative value to report an error to 2064 * the client (although the caller may still need to disconnect after reporting 2065 * the error). 2066 */ 2067 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 2068 Error **errp) 2069 { 2070 NBDClient *client = req->client; 2071 int valid_flags; 2072 2073 g_assert(qemu_in_coroutine()); 2074 assert(client->recv_coroutine == qemu_coroutine_self()); 2075 if (nbd_receive_request(client->ioc, request, errp) < 0) { 2076 return -EIO; 2077 } 2078 2079 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 2080 nbd_cmd_lookup(request->type)); 2081 2082 if (request->type != NBD_CMD_WRITE) { 2083 /* No payload, we are ready to read the next request. */ 2084 req->complete = true; 2085 } 2086 2087 if (request->type == NBD_CMD_DISC) { 2088 /* Special case: we're going to disconnect without a reply, 2089 * whether or not flags, from, or len are bogus */ 2090 return -EIO; 2091 } 2092 2093 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE || 2094 request->type == NBD_CMD_CACHE) 2095 { 2096 if (request->len > NBD_MAX_BUFFER_SIZE) { 2097 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 2098 request->len, NBD_MAX_BUFFER_SIZE); 2099 return -EINVAL; 2100 } 2101 2102 req->data = blk_try_blockalign(client->exp->blk, request->len); 2103 if (req->data == NULL) { 2104 error_setg(errp, "No memory"); 2105 return -ENOMEM; 2106 } 2107 } 2108 if (request->type == NBD_CMD_WRITE) { 2109 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data", 2110 errp) < 0) 2111 { 2112 return -EIO; 2113 } 2114 req->complete = true; 2115 2116 trace_nbd_co_receive_request_payload_received(request->handle, 2117 request->len); 2118 } 2119 2120 /* Sanity checks. */ 2121 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 2122 (request->type == NBD_CMD_WRITE || 2123 request->type == NBD_CMD_WRITE_ZEROES || 2124 request->type == NBD_CMD_TRIM)) { 2125 error_setg(errp, "Export is read-only"); 2126 return -EROFS; 2127 } 2128 if (request->from > client->exp->size || 2129 request->len > client->exp->size - request->from) { 2130 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 2131 ", Size: %" PRIu64, request->from, request->len, 2132 client->exp->size); 2133 return (request->type == NBD_CMD_WRITE || 2134 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2135 } 2136 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len, 2137 client->check_align)) { 2138 /* 2139 * The block layer gracefully handles unaligned requests, but 2140 * it's still worth tracing client non-compliance 2141 */ 2142 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type), 2143 request->from, 2144 request->len, 2145 client->check_align); 2146 } 2147 valid_flags = NBD_CMD_FLAG_FUA; 2148 if (request->type == NBD_CMD_READ && client->structured_reply) { 2149 valid_flags |= NBD_CMD_FLAG_DF; 2150 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 2151 valid_flags |= NBD_CMD_FLAG_NO_HOLE; 2152 } else if (request->type == NBD_CMD_BLOCK_STATUS) { 2153 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2154 } 2155 if (request->flags & ~valid_flags) { 2156 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2157 nbd_cmd_lookup(request->type), request->flags); 2158 return -EINVAL; 2159 } 2160 2161 return 0; 2162 } 2163 2164 /* Send simple reply without a payload, or a structured error 2165 * @error_msg is ignored if @ret >= 0 2166 * Returns 0 if connection is still live, -errno on failure to talk to client 2167 */ 2168 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2169 uint64_t handle, 2170 int ret, 2171 const char *error_msg, 2172 Error **errp) 2173 { 2174 if (client->structured_reply && ret < 0) { 2175 return nbd_co_send_structured_error(client, handle, -ret, error_msg, 2176 errp); 2177 } else { 2178 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0, 2179 NULL, 0, errp); 2180 } 2181 } 2182 2183 /* Handle NBD_CMD_READ request. 2184 * Return -errno if sending fails. Other errors are reported directly to the 2185 * client as an error reply. */ 2186 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2187 uint8_t *data, Error **errp) 2188 { 2189 int ret; 2190 NBDExport *exp = client->exp; 2191 2192 assert(request->type == NBD_CMD_READ || request->type == NBD_CMD_CACHE); 2193 2194 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2195 if (request->flags & NBD_CMD_FLAG_FUA) { 2196 ret = blk_co_flush(exp->blk); 2197 if (ret < 0) { 2198 return nbd_send_generic_reply(client, request->handle, ret, 2199 "flush failed", errp); 2200 } 2201 } 2202 2203 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) && 2204 request->len && request->type != NBD_CMD_CACHE) 2205 { 2206 return nbd_co_send_sparse_read(client, request->handle, request->from, 2207 data, request->len, errp); 2208 } 2209 2210 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data, 2211 request->len); 2212 if (ret < 0 || request->type == NBD_CMD_CACHE) { 2213 return nbd_send_generic_reply(client, request->handle, ret, 2214 "reading from file failed", errp); 2215 } 2216 2217 if (client->structured_reply) { 2218 if (request->len) { 2219 return nbd_co_send_structured_read(client, request->handle, 2220 request->from, data, 2221 request->len, true, errp); 2222 } else { 2223 return nbd_co_send_structured_done(client, request->handle, errp); 2224 } 2225 } else { 2226 return nbd_co_send_simple_reply(client, request->handle, 0, 2227 data, request->len, errp); 2228 } 2229 } 2230 2231 /* Handle NBD request. 2232 * Return -errno if sending fails. Other errors are reported directly to the 2233 * client as an error reply. */ 2234 static coroutine_fn int nbd_handle_request(NBDClient *client, 2235 NBDRequest *request, 2236 uint8_t *data, Error **errp) 2237 { 2238 int ret; 2239 int flags; 2240 NBDExport *exp = client->exp; 2241 char *msg; 2242 2243 switch (request->type) { 2244 case NBD_CMD_READ: 2245 case NBD_CMD_CACHE: 2246 return nbd_do_cmd_read(client, request, data, errp); 2247 2248 case NBD_CMD_WRITE: 2249 flags = 0; 2250 if (request->flags & NBD_CMD_FLAG_FUA) { 2251 flags |= BDRV_REQ_FUA; 2252 } 2253 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset, 2254 data, request->len, flags); 2255 return nbd_send_generic_reply(client, request->handle, ret, 2256 "writing to file failed", errp); 2257 2258 case NBD_CMD_WRITE_ZEROES: 2259 flags = 0; 2260 if (request->flags & NBD_CMD_FLAG_FUA) { 2261 flags |= BDRV_REQ_FUA; 2262 } 2263 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2264 flags |= BDRV_REQ_MAY_UNMAP; 2265 } 2266 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset, 2267 request->len, flags); 2268 return nbd_send_generic_reply(client, request->handle, ret, 2269 "writing to file failed", errp); 2270 2271 case NBD_CMD_DISC: 2272 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2273 abort(); 2274 2275 case NBD_CMD_FLUSH: 2276 ret = blk_co_flush(exp->blk); 2277 return nbd_send_generic_reply(client, request->handle, ret, 2278 "flush failed", errp); 2279 2280 case NBD_CMD_TRIM: 2281 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset, 2282 request->len); 2283 if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) { 2284 ret = blk_co_flush(exp->blk); 2285 } 2286 return nbd_send_generic_reply(client, request->handle, ret, 2287 "discard failed", errp); 2288 2289 case NBD_CMD_BLOCK_STATUS: 2290 if (!request->len) { 2291 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2292 "need non-zero length", errp); 2293 } 2294 if (client->export_meta.valid && 2295 (client->export_meta.base_allocation || 2296 client->export_meta.bitmap)) 2297 { 2298 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2299 2300 if (client->export_meta.base_allocation) { 2301 ret = nbd_co_send_block_status(client, request->handle, 2302 blk_bs(exp->blk), request->from, 2303 request->len, dont_fragment, 2304 !client->export_meta.bitmap, 2305 NBD_META_ID_BASE_ALLOCATION, 2306 errp); 2307 if (ret < 0) { 2308 return ret; 2309 } 2310 } 2311 2312 if (client->export_meta.bitmap) { 2313 ret = nbd_co_send_bitmap(client, request->handle, 2314 client->exp->export_bitmap, 2315 request->from, request->len, 2316 dont_fragment, 2317 true, NBD_META_ID_DIRTY_BITMAP, errp); 2318 if (ret < 0) { 2319 return ret; 2320 } 2321 } 2322 2323 return ret; 2324 } else { 2325 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2326 "CMD_BLOCK_STATUS not negotiated", 2327 errp); 2328 } 2329 2330 default: 2331 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 2332 request->type); 2333 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg, 2334 errp); 2335 g_free(msg); 2336 return ret; 2337 } 2338 } 2339 2340 /* Owns a reference to the NBDClient passed as opaque. */ 2341 static coroutine_fn void nbd_trip(void *opaque) 2342 { 2343 NBDClient *client = opaque; 2344 NBDRequestData *req; 2345 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 2346 int ret; 2347 Error *local_err = NULL; 2348 2349 trace_nbd_trip(); 2350 if (client->closing) { 2351 nbd_client_put(client); 2352 return; 2353 } 2354 2355 req = nbd_request_get(client); 2356 ret = nbd_co_receive_request(req, &request, &local_err); 2357 client->recv_coroutine = NULL; 2358 2359 if (client->closing) { 2360 /* 2361 * The client may be closed when we are blocked in 2362 * nbd_co_receive_request() 2363 */ 2364 goto done; 2365 } 2366 2367 nbd_client_receive_next_request(client); 2368 if (ret == -EIO) { 2369 goto disconnect; 2370 } 2371 2372 if (ret < 0) { 2373 /* It wans't -EIO, so, according to nbd_co_receive_request() 2374 * semantics, we should return the error to the client. */ 2375 Error *export_err = local_err; 2376 2377 local_err = NULL; 2378 ret = nbd_send_generic_reply(client, request.handle, -EINVAL, 2379 error_get_pretty(export_err), &local_err); 2380 error_free(export_err); 2381 } else { 2382 ret = nbd_handle_request(client, &request, req->data, &local_err); 2383 } 2384 if (ret < 0) { 2385 error_prepend(&local_err, "Failed to send reply: "); 2386 goto disconnect; 2387 } 2388 2389 /* We must disconnect after NBD_CMD_WRITE if we did not 2390 * read the payload. 2391 */ 2392 if (!req->complete) { 2393 error_setg(&local_err, "Request handling failed in intermediate state"); 2394 goto disconnect; 2395 } 2396 2397 done: 2398 nbd_request_put(req); 2399 nbd_client_put(client); 2400 return; 2401 2402 disconnect: 2403 if (local_err) { 2404 error_reportf_err(local_err, "Disconnect client, due to: "); 2405 } 2406 nbd_request_put(req); 2407 client_close(client, true); 2408 nbd_client_put(client); 2409 } 2410 2411 static void nbd_client_receive_next_request(NBDClient *client) 2412 { 2413 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 2414 nbd_client_get(client); 2415 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 2416 aio_co_schedule(client->exp->ctx, client->recv_coroutine); 2417 } 2418 } 2419 2420 static coroutine_fn void nbd_co_client_start(void *opaque) 2421 { 2422 NBDClient *client = opaque; 2423 Error *local_err = NULL; 2424 2425 qemu_co_mutex_init(&client->send_lock); 2426 2427 if (nbd_negotiate(client, &local_err)) { 2428 if (local_err) { 2429 error_report_err(local_err); 2430 } 2431 client_close(client, false); 2432 return; 2433 } 2434 2435 nbd_client_receive_next_request(client); 2436 } 2437 2438 /* 2439 * Create a new client listener using the given channel @sioc. 2440 * Begin servicing it in a coroutine. When the connection closes, call 2441 * @close_fn with an indication of whether the client completed negotiation. 2442 */ 2443 void nbd_client_new(QIOChannelSocket *sioc, 2444 QCryptoTLSCreds *tlscreds, 2445 const char *tlsauthz, 2446 void (*close_fn)(NBDClient *, bool)) 2447 { 2448 NBDClient *client; 2449 Coroutine *co; 2450 2451 client = g_new0(NBDClient, 1); 2452 client->refcount = 1; 2453 client->tlscreds = tlscreds; 2454 if (tlscreds) { 2455 object_ref(OBJECT(client->tlscreds)); 2456 } 2457 client->tlsauthz = g_strdup(tlsauthz); 2458 client->sioc = sioc; 2459 object_ref(OBJECT(client->sioc)); 2460 client->ioc = QIO_CHANNEL(sioc); 2461 object_ref(OBJECT(client->ioc)); 2462 client->close_fn = close_fn; 2463 2464 co = qemu_coroutine_create(nbd_co_client_start, client); 2465 qemu_coroutine_enter(co); 2466 } 2467