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 22 #include "block/export.h" 23 #include "qapi/error.h" 24 #include "qemu/queue.h" 25 #include "trace.h" 26 #include "nbd-internal.h" 27 #include "qemu/units.h" 28 29 #define NBD_META_ID_BASE_ALLOCATION 0 30 #define NBD_META_ID_DIRTY_BITMAP 1 31 32 /* 33 * NBD_MAX_BLOCK_STATUS_EXTENTS: 1 MiB of extents data. An empirical 34 * constant. If an increase is needed, note that the NBD protocol 35 * recommends no larger than 32 mb, so that the client won't consider 36 * the reply as a denial of service attack. 37 */ 38 #define NBD_MAX_BLOCK_STATUS_EXTENTS (1 * MiB / 8) 39 40 static int system_errno_to_nbd_errno(int err) 41 { 42 switch (err) { 43 case 0: 44 return NBD_SUCCESS; 45 case EPERM: 46 case EROFS: 47 return NBD_EPERM; 48 case EIO: 49 return NBD_EIO; 50 case ENOMEM: 51 return NBD_ENOMEM; 52 #ifdef EDQUOT 53 case EDQUOT: 54 #endif 55 case EFBIG: 56 case ENOSPC: 57 return NBD_ENOSPC; 58 case EOVERFLOW: 59 return NBD_EOVERFLOW; 60 case ENOTSUP: 61 #if ENOTSUP != EOPNOTSUPP 62 case EOPNOTSUPP: 63 #endif 64 return NBD_ENOTSUP; 65 case ESHUTDOWN: 66 return NBD_ESHUTDOWN; 67 case EINVAL: 68 default: 69 return NBD_EINVAL; 70 } 71 } 72 73 /* Definitions for opaque data types */ 74 75 typedef struct NBDRequestData NBDRequestData; 76 77 struct NBDRequestData { 78 QSIMPLEQ_ENTRY(NBDRequestData) entry; 79 NBDClient *client; 80 uint8_t *data; 81 bool complete; 82 }; 83 84 struct NBDExport { 85 BlockExport common; 86 87 char *name; 88 char *description; 89 uint64_t size; 90 uint16_t nbdflags; 91 QTAILQ_HEAD(, NBDClient) clients; 92 QTAILQ_ENTRY(NBDExport) next; 93 94 BlockBackend *eject_notifier_blk; 95 Notifier eject_notifier; 96 97 BdrvDirtyBitmap *export_bitmap; 98 char *export_bitmap_context; 99 }; 100 101 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); 102 103 /* NBDExportMetaContexts represents a list of contexts to be exported, 104 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for 105 * NBD_OPT_LIST_META_CONTEXT. */ 106 typedef struct NBDExportMetaContexts { 107 NBDExport *exp; 108 bool valid; /* means that negotiation of the option finished without 109 errors */ 110 bool base_allocation; /* export base:allocation context (block status) */ 111 bool bitmap; /* export qemu:dirty-bitmap:<export bitmap name> */ 112 } NBDExportMetaContexts; 113 114 struct NBDClient { 115 int refcount; 116 void (*close_fn)(NBDClient *client, bool negotiated); 117 118 NBDExport *exp; 119 QCryptoTLSCreds *tlscreds; 120 char *tlsauthz; 121 QIOChannelSocket *sioc; /* The underlying data channel */ 122 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ 123 124 Coroutine *recv_coroutine; 125 126 CoMutex send_lock; 127 Coroutine *send_coroutine; 128 129 QTAILQ_ENTRY(NBDClient) next; 130 int nb_requests; 131 bool closing; 132 133 uint32_t check_align; /* If non-zero, check for aligned client requests */ 134 135 bool structured_reply; 136 NBDExportMetaContexts export_meta; 137 138 uint32_t opt; /* Current option being negotiated */ 139 uint32_t optlen; /* remaining length of data in ioc for the option being 140 negotiated now */ 141 }; 142 143 static void nbd_client_receive_next_request(NBDClient *client); 144 145 /* Basic flow for negotiation 146 147 Server Client 148 Negotiate 149 150 or 151 152 Server Client 153 Negotiate #1 154 Option 155 Negotiate #2 156 157 ---- 158 159 followed by 160 161 Server Client 162 Request 163 Response 164 Request 165 Response 166 ... 167 ... 168 Request (type == 2) 169 170 */ 171 172 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option, 173 uint32_t type, uint32_t length) 174 { 175 stq_be_p(&rep->magic, NBD_REP_MAGIC); 176 stl_be_p(&rep->option, option); 177 stl_be_p(&rep->type, type); 178 stl_be_p(&rep->length, length); 179 } 180 181 /* Send a reply header, including length, but no payload. 182 * Return -errno on error, 0 on success. */ 183 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type, 184 uint32_t len, Error **errp) 185 { 186 NBDOptionReply rep; 187 188 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt), 189 type, nbd_rep_lookup(type), len); 190 191 assert(len < NBD_MAX_BUFFER_SIZE); 192 193 set_be_option_rep(&rep, client->opt, type, len); 194 return nbd_write(client->ioc, &rep, sizeof(rep), errp); 195 } 196 197 /* Send a reply header with default 0 length. 198 * Return -errno on error, 0 on success. */ 199 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type, 200 Error **errp) 201 { 202 return nbd_negotiate_send_rep_len(client, type, 0, errp); 203 } 204 205 /* Send an error reply. 206 * Return -errno on error, 0 on success. */ 207 static int GCC_FMT_ATTR(4, 0) 208 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, 209 Error **errp, const char *fmt, va_list va) 210 { 211 ERRP_GUARD(); 212 g_autofree char *msg = NULL; 213 int ret; 214 size_t len; 215 216 msg = g_strdup_vprintf(fmt, va); 217 len = strlen(msg); 218 assert(len < NBD_MAX_STRING_SIZE); 219 trace_nbd_negotiate_send_rep_err(msg); 220 ret = nbd_negotiate_send_rep_len(client, type, len, errp); 221 if (ret < 0) { 222 return ret; 223 } 224 if (nbd_write(client->ioc, msg, len, errp) < 0) { 225 error_prepend(errp, "write failed (error message): "); 226 return -EIO; 227 } 228 229 return 0; 230 } 231 232 /* 233 * Return a malloc'd copy of @name suitable for use in an error reply. 234 */ 235 static char * 236 nbd_sanitize_name(const char *name) 237 { 238 if (strnlen(name, 80) < 80) { 239 return g_strdup(name); 240 } 241 /* XXX Should we also try to sanitize any control characters? */ 242 return g_strdup_printf("%.80s...", name); 243 } 244 245 /* Send an error reply. 246 * Return -errno on error, 0 on success. */ 247 static int GCC_FMT_ATTR(4, 5) 248 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type, 249 Error **errp, const char *fmt, ...) 250 { 251 va_list va; 252 int ret; 253 254 va_start(va, fmt); 255 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 256 va_end(va); 257 return ret; 258 } 259 260 /* Drop remainder of the current option, and send a reply with the 261 * given error type and message. Return -errno on read or write 262 * failure; or 0 if connection is still live. */ 263 static int GCC_FMT_ATTR(4, 0) 264 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp, 265 const char *fmt, va_list va) 266 { 267 int ret = nbd_drop(client->ioc, client->optlen, errp); 268 269 client->optlen = 0; 270 if (!ret) { 271 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 272 } 273 return ret; 274 } 275 276 static int GCC_FMT_ATTR(4, 5) 277 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp, 278 const char *fmt, ...) 279 { 280 int ret; 281 va_list va; 282 283 va_start(va, fmt); 284 ret = nbd_opt_vdrop(client, type, errp, fmt, va); 285 va_end(va); 286 287 return ret; 288 } 289 290 static int GCC_FMT_ATTR(3, 4) 291 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...) 292 { 293 int ret; 294 va_list va; 295 296 va_start(va, fmt); 297 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va); 298 va_end(va); 299 300 return ret; 301 } 302 303 /* Read size bytes from the unparsed payload of the current option. 304 * Return -errno on I/O error, 0 if option was completely handled by 305 * sending a reply about inconsistent lengths, or 1 on success. */ 306 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size, 307 Error **errp) 308 { 309 if (size > client->optlen) { 310 return nbd_opt_invalid(client, errp, 311 "Inconsistent lengths in option %s", 312 nbd_opt_lookup(client->opt)); 313 } 314 client->optlen -= size; 315 return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1; 316 } 317 318 /* Drop size bytes from the unparsed payload of the current option. 319 * Return -errno on I/O error, 0 if option was completely handled by 320 * sending a reply about inconsistent lengths, or 1 on success. */ 321 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp) 322 { 323 if (size > client->optlen) { 324 return nbd_opt_invalid(client, errp, 325 "Inconsistent lengths in option %s", 326 nbd_opt_lookup(client->opt)); 327 } 328 client->optlen -= size; 329 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1; 330 } 331 332 /* nbd_opt_read_name 333 * 334 * Read a string with the format: 335 * uint32_t len (<= NBD_MAX_STRING_SIZE) 336 * len bytes string (not 0-terminated) 337 * 338 * On success, @name will be allocated. 339 * If @length is non-null, it will be set to the actual string length. 340 * 341 * Return -errno on I/O error, 0 if option was completely handled by 342 * sending a reply about inconsistent lengths, or 1 on success. 343 */ 344 static int nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length, 345 Error **errp) 346 { 347 int ret; 348 uint32_t len; 349 g_autofree char *local_name = NULL; 350 351 *name = NULL; 352 ret = nbd_opt_read(client, &len, sizeof(len), errp); 353 if (ret <= 0) { 354 return ret; 355 } 356 len = cpu_to_be32(len); 357 358 if (len > NBD_MAX_STRING_SIZE) { 359 return nbd_opt_invalid(client, errp, 360 "Invalid name length: %" PRIu32, len); 361 } 362 363 local_name = g_malloc(len + 1); 364 ret = nbd_opt_read(client, local_name, len, errp); 365 if (ret <= 0) { 366 return ret; 367 } 368 local_name[len] = '\0'; 369 370 if (length) { 371 *length = len; 372 } 373 *name = g_steal_pointer(&local_name); 374 375 return 1; 376 } 377 378 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 379 * Return -errno on error, 0 on success. */ 380 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, 381 Error **errp) 382 { 383 ERRP_GUARD(); 384 size_t name_len, desc_len; 385 uint32_t len; 386 const char *name = exp->name ? exp->name : ""; 387 const char *desc = exp->description ? exp->description : ""; 388 QIOChannel *ioc = client->ioc; 389 int ret; 390 391 trace_nbd_negotiate_send_rep_list(name, desc); 392 name_len = strlen(name); 393 desc_len = strlen(desc); 394 assert(name_len <= NBD_MAX_STRING_SIZE && desc_len <= NBD_MAX_STRING_SIZE); 395 len = name_len + desc_len + sizeof(len); 396 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp); 397 if (ret < 0) { 398 return ret; 399 } 400 401 len = cpu_to_be32(name_len); 402 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 403 error_prepend(errp, "write failed (name length): "); 404 return -EINVAL; 405 } 406 407 if (nbd_write(ioc, name, name_len, errp) < 0) { 408 error_prepend(errp, "write failed (name buffer): "); 409 return -EINVAL; 410 } 411 412 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 413 error_prepend(errp, "write failed (description buffer): "); 414 return -EINVAL; 415 } 416 417 return 0; 418 } 419 420 /* Process the NBD_OPT_LIST command, with a potential series of replies. 421 * Return -errno on error, 0 on success. */ 422 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) 423 { 424 NBDExport *exp; 425 assert(client->opt == NBD_OPT_LIST); 426 427 /* For each export, send a NBD_REP_SERVER reply. */ 428 QTAILQ_FOREACH(exp, &exports, next) { 429 if (nbd_negotiate_send_rep_list(client, exp, errp)) { 430 return -EINVAL; 431 } 432 } 433 /* Finish with a NBD_REP_ACK. */ 434 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 435 } 436 437 static void nbd_check_meta_export(NBDClient *client) 438 { 439 client->export_meta.valid &= client->exp == client->export_meta.exp; 440 } 441 442 /* Send a reply to NBD_OPT_EXPORT_NAME. 443 * Return -errno on error, 0 on success. */ 444 static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes, 445 Error **errp) 446 { 447 ERRP_GUARD(); 448 g_autofree char *name = NULL; 449 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 450 size_t len; 451 int ret; 452 uint16_t myflags; 453 454 /* Client sends: 455 [20 .. xx] export name (length bytes) 456 Server replies: 457 [ 0 .. 7] size 458 [ 8 .. 9] export flags 459 [10 .. 133] reserved (0) [unless no_zeroes] 460 */ 461 trace_nbd_negotiate_handle_export_name(); 462 if (client->optlen > NBD_MAX_STRING_SIZE) { 463 error_setg(errp, "Bad length received"); 464 return -EINVAL; 465 } 466 name = g_malloc(client->optlen + 1); 467 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) { 468 return -EIO; 469 } 470 name[client->optlen] = '\0'; 471 client->optlen = 0; 472 473 trace_nbd_negotiate_handle_export_name_request(name); 474 475 client->exp = nbd_export_find(name); 476 if (!client->exp) { 477 error_setg(errp, "export not found"); 478 return -EINVAL; 479 } 480 481 myflags = client->exp->nbdflags; 482 if (client->structured_reply) { 483 myflags |= NBD_FLAG_SEND_DF; 484 } 485 trace_nbd_negotiate_new_style_size_flags(client->exp->size, myflags); 486 stq_be_p(buf, client->exp->size); 487 stw_be_p(buf + 8, myflags); 488 len = no_zeroes ? 10 : sizeof(buf); 489 ret = nbd_write(client->ioc, buf, len, errp); 490 if (ret < 0) { 491 error_prepend(errp, "write failed: "); 492 return ret; 493 } 494 495 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 496 blk_exp_ref(&client->exp->common); 497 nbd_check_meta_export(client); 498 499 return 0; 500 } 501 502 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 503 * The buffer does NOT include the info type prefix. 504 * Return -errno on error, 0 if ready to send more. */ 505 static int nbd_negotiate_send_info(NBDClient *client, 506 uint16_t info, uint32_t length, void *buf, 507 Error **errp) 508 { 509 int rc; 510 511 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 512 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 513 sizeof(info) + length, errp); 514 if (rc < 0) { 515 return rc; 516 } 517 info = cpu_to_be16(info); 518 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 519 return -EIO; 520 } 521 if (nbd_write(client->ioc, buf, length, errp) < 0) { 522 return -EIO; 523 } 524 return 0; 525 } 526 527 /* nbd_reject_length: Handle any unexpected payload. 528 * @fatal requests that we quit talking to the client, even if we are able 529 * to successfully send an error reply. 530 * Return: 531 * -errno transmission error occurred or @fatal was requested, errp is set 532 * 0 error message successfully sent to client, errp is not set 533 */ 534 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 535 { 536 int ret; 537 538 assert(client->optlen); 539 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length", 540 nbd_opt_lookup(client->opt)); 541 if (fatal && !ret) { 542 error_setg(errp, "option '%s' has unexpected length", 543 nbd_opt_lookup(client->opt)); 544 return -EINVAL; 545 } 546 return ret; 547 } 548 549 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 550 * Return -errno on error, 0 if ready for next option, and 1 to move 551 * into transmission phase. */ 552 static int nbd_negotiate_handle_info(NBDClient *client, Error **errp) 553 { 554 int rc; 555 g_autofree char *name = NULL; 556 NBDExport *exp; 557 uint16_t requests; 558 uint16_t request; 559 uint32_t namelen; 560 bool sendname = false; 561 bool blocksize = false; 562 uint32_t sizes[3]; 563 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 564 uint32_t check_align = 0; 565 uint16_t myflags; 566 567 /* Client sends: 568 4 bytes: L, name length (can be 0) 569 L bytes: export name 570 2 bytes: N, number of requests (can be 0) 571 N * 2 bytes: N requests 572 */ 573 rc = nbd_opt_read_name(client, &name, &namelen, errp); 574 if (rc <= 0) { 575 return rc; 576 } 577 trace_nbd_negotiate_handle_export_name_request(name); 578 579 rc = nbd_opt_read(client, &requests, sizeof(requests), errp); 580 if (rc <= 0) { 581 return rc; 582 } 583 requests = be16_to_cpu(requests); 584 trace_nbd_negotiate_handle_info_requests(requests); 585 while (requests--) { 586 rc = nbd_opt_read(client, &request, sizeof(request), errp); 587 if (rc <= 0) { 588 return rc; 589 } 590 request = be16_to_cpu(request); 591 trace_nbd_negotiate_handle_info_request(request, 592 nbd_info_lookup(request)); 593 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 594 * everything else is either a request we don't know or 595 * something we send regardless of request */ 596 switch (request) { 597 case NBD_INFO_NAME: 598 sendname = true; 599 break; 600 case NBD_INFO_BLOCK_SIZE: 601 blocksize = true; 602 break; 603 } 604 } 605 if (client->optlen) { 606 return nbd_reject_length(client, false, errp); 607 } 608 609 exp = nbd_export_find(name); 610 if (!exp) { 611 g_autofree char *sane_name = nbd_sanitize_name(name); 612 613 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 614 errp, "export '%s' not present", 615 sane_name); 616 } 617 618 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 619 if (sendname) { 620 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 621 errp); 622 if (rc < 0) { 623 return rc; 624 } 625 } 626 627 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 628 * client request */ 629 if (exp->description) { 630 size_t len = strlen(exp->description); 631 632 assert(len <= NBD_MAX_STRING_SIZE); 633 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 634 len, exp->description, errp); 635 if (rc < 0) { 636 return rc; 637 } 638 } 639 640 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 641 * according to whether the client requested it, and according to 642 * whether this is OPT_INFO or OPT_GO. */ 643 /* minimum - 1 for back-compat, or actual if client will obey it. */ 644 if (client->opt == NBD_OPT_INFO || blocksize) { 645 check_align = sizes[0] = blk_get_request_alignment(exp->common.blk); 646 } else { 647 sizes[0] = 1; 648 } 649 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE); 650 /* preferred - Hard-code to 4096 for now. 651 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 652 sizes[1] = MAX(4096, sizes[0]); 653 /* maximum - At most 32M, but smaller as appropriate. */ 654 sizes[2] = MIN(blk_get_max_transfer(exp->common.blk), NBD_MAX_BUFFER_SIZE); 655 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 656 sizes[0] = cpu_to_be32(sizes[0]); 657 sizes[1] = cpu_to_be32(sizes[1]); 658 sizes[2] = cpu_to_be32(sizes[2]); 659 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 660 sizeof(sizes), sizes, errp); 661 if (rc < 0) { 662 return rc; 663 } 664 665 /* Send NBD_INFO_EXPORT always */ 666 myflags = exp->nbdflags; 667 if (client->structured_reply) { 668 myflags |= NBD_FLAG_SEND_DF; 669 } 670 trace_nbd_negotiate_new_style_size_flags(exp->size, myflags); 671 stq_be_p(buf, exp->size); 672 stw_be_p(buf + 8, myflags); 673 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 674 sizeof(buf), buf, errp); 675 if (rc < 0) { 676 return rc; 677 } 678 679 /* 680 * If the client is just asking for NBD_OPT_INFO, but forgot to 681 * request block sizes in a situation that would impact 682 * performance, then return an error. But for NBD_OPT_GO, we 683 * tolerate all clients, regardless of alignments. 684 */ 685 if (client->opt == NBD_OPT_INFO && !blocksize && 686 blk_get_request_alignment(exp->common.blk) > 1) { 687 return nbd_negotiate_send_rep_err(client, 688 NBD_REP_ERR_BLOCK_SIZE_REQD, 689 errp, 690 "request NBD_INFO_BLOCK_SIZE to " 691 "use this export"); 692 } 693 694 /* Final reply */ 695 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 696 if (rc < 0) { 697 return rc; 698 } 699 700 if (client->opt == NBD_OPT_GO) { 701 client->exp = exp; 702 client->check_align = check_align; 703 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 704 blk_exp_ref(&client->exp->common); 705 nbd_check_meta_export(client); 706 rc = 1; 707 } 708 return rc; 709 } 710 711 712 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 713 * new channel for all further (now-encrypted) communication. */ 714 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 715 Error **errp) 716 { 717 QIOChannel *ioc; 718 QIOChannelTLS *tioc; 719 struct NBDTLSHandshakeData data = { 0 }; 720 721 assert(client->opt == NBD_OPT_STARTTLS); 722 723 trace_nbd_negotiate_handle_starttls(); 724 ioc = client->ioc; 725 726 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 727 return NULL; 728 } 729 730 tioc = qio_channel_tls_new_server(ioc, 731 client->tlscreds, 732 client->tlsauthz, 733 errp); 734 if (!tioc) { 735 return NULL; 736 } 737 738 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 739 trace_nbd_negotiate_handle_starttls_handshake(); 740 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 741 qio_channel_tls_handshake(tioc, 742 nbd_tls_handshake, 743 &data, 744 NULL, 745 NULL); 746 747 if (!data.complete) { 748 g_main_loop_run(data.loop); 749 } 750 g_main_loop_unref(data.loop); 751 if (data.error) { 752 object_unref(OBJECT(tioc)); 753 error_propagate(errp, data.error); 754 return NULL; 755 } 756 757 return QIO_CHANNEL(tioc); 758 } 759 760 /* nbd_negotiate_send_meta_context 761 * 762 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT 763 * 764 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead. 765 */ 766 static int nbd_negotiate_send_meta_context(NBDClient *client, 767 const char *context, 768 uint32_t context_id, 769 Error **errp) 770 { 771 NBDOptionReplyMetaContext opt; 772 struct iovec iov[] = { 773 {.iov_base = &opt, .iov_len = sizeof(opt)}, 774 {.iov_base = (void *)context, .iov_len = strlen(context)} 775 }; 776 777 assert(iov[1].iov_len <= NBD_MAX_STRING_SIZE); 778 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 779 context_id = 0; 780 } 781 782 trace_nbd_negotiate_meta_query_reply(context, context_id); 783 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT, 784 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len); 785 stl_be_p(&opt.context_id, context_id); 786 787 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; 788 } 789 790 /* Read strlen(@pattern) bytes, and set @match to true if they match @pattern. 791 * @match is never set to false. 792 * 793 * Return -errno on I/O error, 0 if option was completely handled by 794 * sending a reply about inconsistent lengths, or 1 on success. 795 * 796 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 797 * It only means that there are no errors. 798 */ 799 static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match, 800 Error **errp) 801 { 802 int ret; 803 char *query; 804 size_t len = strlen(pattern); 805 806 assert(len); 807 808 query = g_malloc(len); 809 ret = nbd_opt_read(client, query, len, errp); 810 if (ret <= 0) { 811 g_free(query); 812 return ret; 813 } 814 815 if (strncmp(query, pattern, len) == 0) { 816 trace_nbd_negotiate_meta_query_parse(pattern); 817 *match = true; 818 } else { 819 trace_nbd_negotiate_meta_query_skip("pattern not matched"); 820 } 821 g_free(query); 822 823 return 1; 824 } 825 826 /* 827 * Read @len bytes, and set @match to true if they match @pattern, or if @len 828 * is 0 and the client is performing _LIST_. @match is never set to false. 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 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 834 * It only means that there are no errors. 835 */ 836 static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, 837 uint32_t len, bool *match, Error **errp) 838 { 839 if (len == 0) { 840 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 841 *match = true; 842 } 843 trace_nbd_negotiate_meta_query_parse("empty"); 844 return 1; 845 } 846 847 if (len != strlen(pattern)) { 848 trace_nbd_negotiate_meta_query_skip("different lengths"); 849 return nbd_opt_skip(client, len, errp); 850 } 851 852 return nbd_meta_pattern(client, pattern, match, errp); 853 } 854 855 /* nbd_meta_base_query 856 * 857 * Handle queries to 'base' namespace. For now, only the base:allocation 858 * context is available. 'len' is the amount of text remaining to be read from 859 * the current name, after the 'base:' portion has been stripped. 860 * 861 * Return -errno on I/O error, 0 if option was completely handled by 862 * sending a reply about inconsistent lengths, or 1 on success. 863 */ 864 static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta, 865 uint32_t len, Error **errp) 866 { 867 return nbd_meta_empty_or_pattern(client, "allocation", len, 868 &meta->base_allocation, errp); 869 } 870 871 /* nbd_meta_bitmap_query 872 * 873 * Handle query to 'qemu:' namespace. 874 * @len is the amount of text remaining to be read from the current name, after 875 * the 'qemu:' portion has been stripped. 876 * 877 * Return -errno on I/O error, 0 if option was completely handled by 878 * sending a reply about inconsistent lengths, or 1 on success. */ 879 static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta, 880 uint32_t len, Error **errp) 881 { 882 bool dirty_bitmap = false; 883 size_t dirty_bitmap_len = strlen("dirty-bitmap:"); 884 int ret; 885 886 if (!meta->exp->export_bitmap) { 887 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported"); 888 return nbd_opt_skip(client, len, errp); 889 } 890 891 if (len == 0) { 892 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 893 meta->bitmap = true; 894 } 895 trace_nbd_negotiate_meta_query_parse("empty"); 896 return 1; 897 } 898 899 if (len < dirty_bitmap_len) { 900 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 901 return nbd_opt_skip(client, len, errp); 902 } 903 904 len -= dirty_bitmap_len; 905 ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp); 906 if (ret <= 0) { 907 return ret; 908 } 909 if (!dirty_bitmap) { 910 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 911 return nbd_opt_skip(client, len, errp); 912 } 913 914 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); 915 916 return nbd_meta_empty_or_pattern( 917 client, meta->exp->export_bitmap_context + 918 strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp); 919 } 920 921 /* nbd_negotiate_meta_query 922 * 923 * Parse namespace name and call corresponding function to parse body of the 924 * query. 925 * 926 * The only supported namespaces are 'base' and 'qemu'. 927 * 928 * The function aims not wasting time and memory to read long unknown namespace 929 * names. 930 * 931 * Return -errno on I/O error, 0 if option was completely handled by 932 * sending a reply about inconsistent lengths, or 1 on success. */ 933 static int nbd_negotiate_meta_query(NBDClient *client, 934 NBDExportMetaContexts *meta, Error **errp) 935 { 936 /* 937 * Both 'qemu' and 'base' namespaces have length = 5 including a 938 * colon. If another length namespace is later introduced, this 939 * should certainly be refactored. 940 */ 941 int ret; 942 size_t ns_len = 5; 943 char ns[5]; 944 uint32_t len; 945 946 ret = nbd_opt_read(client, &len, sizeof(len), errp); 947 if (ret <= 0) { 948 return ret; 949 } 950 len = cpu_to_be32(len); 951 952 if (len > NBD_MAX_STRING_SIZE) { 953 trace_nbd_negotiate_meta_query_skip("length too long"); 954 return nbd_opt_skip(client, len, errp); 955 } 956 if (len < ns_len) { 957 trace_nbd_negotiate_meta_query_skip("length too short"); 958 return nbd_opt_skip(client, len, errp); 959 } 960 961 len -= ns_len; 962 ret = nbd_opt_read(client, ns, ns_len, errp); 963 if (ret <= 0) { 964 return ret; 965 } 966 967 if (!strncmp(ns, "base:", ns_len)) { 968 trace_nbd_negotiate_meta_query_parse("base:"); 969 return nbd_meta_base_query(client, meta, len, errp); 970 } else if (!strncmp(ns, "qemu:", ns_len)) { 971 trace_nbd_negotiate_meta_query_parse("qemu:"); 972 return nbd_meta_qemu_query(client, meta, len, errp); 973 } 974 975 trace_nbd_negotiate_meta_query_skip("unknown namespace"); 976 return nbd_opt_skip(client, len, errp); 977 } 978 979 /* nbd_negotiate_meta_queries 980 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT 981 * 982 * Return -errno on I/O error, or 0 if option was completely handled. */ 983 static int nbd_negotiate_meta_queries(NBDClient *client, 984 NBDExportMetaContexts *meta, Error **errp) 985 { 986 int ret; 987 g_autofree char *export_name = NULL; 988 NBDExportMetaContexts local_meta; 989 uint32_t nb_queries; 990 int i; 991 992 if (!client->structured_reply) { 993 return nbd_opt_invalid(client, errp, 994 "request option '%s' when structured reply " 995 "is not negotiated", 996 nbd_opt_lookup(client->opt)); 997 } 998 999 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 1000 /* Only change the caller's meta on SET. */ 1001 meta = &local_meta; 1002 } 1003 1004 memset(meta, 0, sizeof(*meta)); 1005 1006 ret = nbd_opt_read_name(client, &export_name, NULL, errp); 1007 if (ret <= 0) { 1008 return ret; 1009 } 1010 1011 meta->exp = nbd_export_find(export_name); 1012 if (meta->exp == NULL) { 1013 g_autofree char *sane_name = nbd_sanitize_name(export_name); 1014 1015 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, 1016 "export '%s' not present", sane_name); 1017 } 1018 1019 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp); 1020 if (ret <= 0) { 1021 return ret; 1022 } 1023 nb_queries = cpu_to_be32(nb_queries); 1024 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), 1025 export_name, nb_queries); 1026 1027 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { 1028 /* enable all known contexts */ 1029 meta->base_allocation = true; 1030 meta->bitmap = !!meta->exp->export_bitmap; 1031 } else { 1032 for (i = 0; i < nb_queries; ++i) { 1033 ret = nbd_negotiate_meta_query(client, meta, errp); 1034 if (ret <= 0) { 1035 return ret; 1036 } 1037 } 1038 } 1039 1040 if (meta->base_allocation) { 1041 ret = nbd_negotiate_send_meta_context(client, "base:allocation", 1042 NBD_META_ID_BASE_ALLOCATION, 1043 errp); 1044 if (ret < 0) { 1045 return ret; 1046 } 1047 } 1048 1049 if (meta->bitmap) { 1050 ret = nbd_negotiate_send_meta_context(client, 1051 meta->exp->export_bitmap_context, 1052 NBD_META_ID_DIRTY_BITMAP, 1053 errp); 1054 if (ret < 0) { 1055 return ret; 1056 } 1057 } 1058 1059 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1060 if (ret == 0) { 1061 meta->valid = true; 1062 } 1063 1064 return ret; 1065 } 1066 1067 /* nbd_negotiate_options 1068 * Process all NBD_OPT_* client option commands, during fixed newstyle 1069 * negotiation. 1070 * Return: 1071 * -errno on error, errp is set 1072 * 0 on successful negotiation, errp is not set 1073 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1074 * errp is not set 1075 */ 1076 static int nbd_negotiate_options(NBDClient *client, Error **errp) 1077 { 1078 uint32_t flags; 1079 bool fixedNewstyle = false; 1080 bool no_zeroes = false; 1081 1082 /* Client sends: 1083 [ 0 .. 3] client flags 1084 1085 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 1086 [ 0 .. 7] NBD_OPTS_MAGIC 1087 [ 8 .. 11] NBD option 1088 [12 .. 15] Data length 1089 ... Rest of request 1090 1091 [ 0 .. 7] NBD_OPTS_MAGIC 1092 [ 8 .. 11] Second NBD option 1093 [12 .. 15] Data length 1094 ... Rest of request 1095 */ 1096 1097 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) { 1098 return -EIO; 1099 } 1100 trace_nbd_negotiate_options_flags(flags); 1101 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1102 fixedNewstyle = true; 1103 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1104 } 1105 if (flags & NBD_FLAG_C_NO_ZEROES) { 1106 no_zeroes = true; 1107 flags &= ~NBD_FLAG_C_NO_ZEROES; 1108 } 1109 if (flags != 0) { 1110 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1111 return -EINVAL; 1112 } 1113 1114 while (1) { 1115 int ret; 1116 uint32_t option, length; 1117 uint64_t magic; 1118 1119 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) { 1120 return -EINVAL; 1121 } 1122 trace_nbd_negotiate_options_check_magic(magic); 1123 if (magic != NBD_OPTS_MAGIC) { 1124 error_setg(errp, "Bad magic received"); 1125 return -EINVAL; 1126 } 1127 1128 if (nbd_read32(client->ioc, &option, "option", errp) < 0) { 1129 return -EINVAL; 1130 } 1131 client->opt = option; 1132 1133 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) { 1134 return -EINVAL; 1135 } 1136 assert(!client->optlen); 1137 client->optlen = length; 1138 1139 if (length > NBD_MAX_BUFFER_SIZE) { 1140 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1141 length, NBD_MAX_BUFFER_SIZE); 1142 return -EINVAL; 1143 } 1144 1145 trace_nbd_negotiate_options_check_option(option, 1146 nbd_opt_lookup(option)); 1147 if (client->tlscreds && 1148 client->ioc == (QIOChannel *)client->sioc) { 1149 QIOChannel *tioc; 1150 if (!fixedNewstyle) { 1151 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1152 return -EINVAL; 1153 } 1154 switch (option) { 1155 case NBD_OPT_STARTTLS: 1156 if (length) { 1157 /* Unconditionally drop the connection if the client 1158 * can't start a TLS negotiation correctly */ 1159 return nbd_reject_length(client, true, errp); 1160 } 1161 tioc = nbd_negotiate_handle_starttls(client, errp); 1162 if (!tioc) { 1163 return -EIO; 1164 } 1165 ret = 0; 1166 object_unref(OBJECT(client->ioc)); 1167 client->ioc = QIO_CHANNEL(tioc); 1168 break; 1169 1170 case NBD_OPT_EXPORT_NAME: 1171 /* No way to return an error to client, so drop connection */ 1172 error_setg(errp, "Option 0x%x not permitted before TLS", 1173 option); 1174 return -EINVAL; 1175 1176 default: 1177 /* Let the client keep trying, unless they asked to 1178 * quit. Always try to give an error back to the 1179 * client; but when replying to OPT_ABORT, be aware 1180 * that the client may hang up before receiving the 1181 * error, in which case we are fine ignoring the 1182 * resulting EPIPE. */ 1183 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, 1184 option == NBD_OPT_ABORT ? NULL : errp, 1185 "Option 0x%" PRIx32 1186 " not permitted before TLS", option); 1187 if (option == NBD_OPT_ABORT) { 1188 return 1; 1189 } 1190 break; 1191 } 1192 } else if (fixedNewstyle) { 1193 switch (option) { 1194 case NBD_OPT_LIST: 1195 if (length) { 1196 ret = nbd_reject_length(client, false, errp); 1197 } else { 1198 ret = nbd_negotiate_handle_list(client, errp); 1199 } 1200 break; 1201 1202 case NBD_OPT_ABORT: 1203 /* NBD spec says we must try to reply before 1204 * disconnecting, but that we must also tolerate 1205 * guests that don't wait for our reply. */ 1206 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1207 return 1; 1208 1209 case NBD_OPT_EXPORT_NAME: 1210 return nbd_negotiate_handle_export_name(client, no_zeroes, 1211 errp); 1212 1213 case NBD_OPT_INFO: 1214 case NBD_OPT_GO: 1215 ret = nbd_negotiate_handle_info(client, errp); 1216 if (ret == 1) { 1217 assert(option == NBD_OPT_GO); 1218 return 0; 1219 } 1220 break; 1221 1222 case NBD_OPT_STARTTLS: 1223 if (length) { 1224 ret = nbd_reject_length(client, false, errp); 1225 } else if (client->tlscreds) { 1226 ret = nbd_negotiate_send_rep_err(client, 1227 NBD_REP_ERR_INVALID, errp, 1228 "TLS already enabled"); 1229 } else { 1230 ret = nbd_negotiate_send_rep_err(client, 1231 NBD_REP_ERR_POLICY, errp, 1232 "TLS not configured"); 1233 } 1234 break; 1235 1236 case NBD_OPT_STRUCTURED_REPLY: 1237 if (length) { 1238 ret = nbd_reject_length(client, false, errp); 1239 } else if (client->structured_reply) { 1240 ret = nbd_negotiate_send_rep_err( 1241 client, NBD_REP_ERR_INVALID, errp, 1242 "structured reply already negotiated"); 1243 } else { 1244 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1245 client->structured_reply = true; 1246 } 1247 break; 1248 1249 case NBD_OPT_LIST_META_CONTEXT: 1250 case NBD_OPT_SET_META_CONTEXT: 1251 ret = nbd_negotiate_meta_queries(client, &client->export_meta, 1252 errp); 1253 break; 1254 1255 default: 1256 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1257 "Unsupported option %" PRIu32 " (%s)", 1258 option, nbd_opt_lookup(option)); 1259 break; 1260 } 1261 } else { 1262 /* 1263 * If broken new-style we should drop the connection 1264 * for anything except NBD_OPT_EXPORT_NAME 1265 */ 1266 switch (option) { 1267 case NBD_OPT_EXPORT_NAME: 1268 return nbd_negotiate_handle_export_name(client, no_zeroes, 1269 errp); 1270 1271 default: 1272 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1273 option, nbd_opt_lookup(option)); 1274 return -EINVAL; 1275 } 1276 } 1277 if (ret < 0) { 1278 return ret; 1279 } 1280 } 1281 } 1282 1283 /* nbd_negotiate 1284 * Return: 1285 * -errno on error, errp is set 1286 * 0 on successful negotiation, errp is not set 1287 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1288 * errp is not set 1289 */ 1290 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1291 { 1292 ERRP_GUARD(); 1293 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1294 int ret; 1295 1296 /* Old style negotiation header, no room for options 1297 [ 0 .. 7] passwd ("NBDMAGIC") 1298 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1299 [16 .. 23] size 1300 [24 .. 27] export flags (zero-extended) 1301 [28 .. 151] reserved (0) 1302 1303 New style negotiation header, client can send options 1304 [ 0 .. 7] passwd ("NBDMAGIC") 1305 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1306 [16 .. 17] server flags (0) 1307 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1308 */ 1309 1310 qio_channel_set_blocking(client->ioc, false, NULL); 1311 1312 trace_nbd_negotiate_begin(); 1313 memcpy(buf, "NBDMAGIC", 8); 1314 1315 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1316 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1317 1318 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 1319 error_prepend(errp, "write failed: "); 1320 return -EINVAL; 1321 } 1322 ret = nbd_negotiate_options(client, errp); 1323 if (ret != 0) { 1324 if (ret < 0) { 1325 error_prepend(errp, "option negotiation failed: "); 1326 } 1327 return ret; 1328 } 1329 1330 /* Attach the channel to the same AioContext as the export */ 1331 if (client->exp && client->exp->common.ctx) { 1332 qio_channel_attach_aio_context(client->ioc, client->exp->common.ctx); 1333 } 1334 1335 assert(!client->optlen); 1336 trace_nbd_negotiate_success(); 1337 1338 return 0; 1339 } 1340 1341 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 1342 Error **errp) 1343 { 1344 uint8_t buf[NBD_REQUEST_SIZE]; 1345 uint32_t magic; 1346 int ret; 1347 1348 ret = nbd_read(ioc, buf, sizeof(buf), "request", errp); 1349 if (ret < 0) { 1350 return ret; 1351 } 1352 1353 /* Request 1354 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1355 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1356 [ 6 .. 7] type (NBD_CMD_READ, ...) 1357 [ 8 .. 15] handle 1358 [16 .. 23] from 1359 [24 .. 27] len 1360 */ 1361 1362 magic = ldl_be_p(buf); 1363 request->flags = lduw_be_p(buf + 4); 1364 request->type = lduw_be_p(buf + 6); 1365 request->handle = ldq_be_p(buf + 8); 1366 request->from = ldq_be_p(buf + 16); 1367 request->len = ldl_be_p(buf + 24); 1368 1369 trace_nbd_receive_request(magic, request->flags, request->type, 1370 request->from, request->len); 1371 1372 if (magic != NBD_REQUEST_MAGIC) { 1373 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 1374 return -EINVAL; 1375 } 1376 return 0; 1377 } 1378 1379 #define MAX_NBD_REQUESTS 16 1380 1381 void nbd_client_get(NBDClient *client) 1382 { 1383 client->refcount++; 1384 } 1385 1386 void nbd_client_put(NBDClient *client) 1387 { 1388 if (--client->refcount == 0) { 1389 /* The last reference should be dropped by client->close, 1390 * which is called by client_close. 1391 */ 1392 assert(client->closing); 1393 1394 qio_channel_detach_aio_context(client->ioc); 1395 object_unref(OBJECT(client->sioc)); 1396 object_unref(OBJECT(client->ioc)); 1397 if (client->tlscreds) { 1398 object_unref(OBJECT(client->tlscreds)); 1399 } 1400 g_free(client->tlsauthz); 1401 if (client->exp) { 1402 QTAILQ_REMOVE(&client->exp->clients, client, next); 1403 blk_exp_unref(&client->exp->common); 1404 } 1405 g_free(client); 1406 } 1407 } 1408 1409 static void client_close(NBDClient *client, bool negotiated) 1410 { 1411 if (client->closing) { 1412 return; 1413 } 1414 1415 client->closing = true; 1416 1417 /* Force requests to finish. They will drop their own references, 1418 * then we'll close the socket and free the NBDClient. 1419 */ 1420 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1421 NULL); 1422 1423 /* Also tell the client, so that they release their reference. */ 1424 if (client->close_fn) { 1425 client->close_fn(client, negotiated); 1426 } 1427 } 1428 1429 static NBDRequestData *nbd_request_get(NBDClient *client) 1430 { 1431 NBDRequestData *req; 1432 1433 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1434 client->nb_requests++; 1435 1436 req = g_new0(NBDRequestData, 1); 1437 nbd_client_get(client); 1438 req->client = client; 1439 return req; 1440 } 1441 1442 static void nbd_request_put(NBDRequestData *req) 1443 { 1444 NBDClient *client = req->client; 1445 1446 if (req->data) { 1447 qemu_vfree(req->data); 1448 } 1449 g_free(req); 1450 1451 client->nb_requests--; 1452 nbd_client_receive_next_request(client); 1453 1454 nbd_client_put(client); 1455 } 1456 1457 static void blk_aio_attached(AioContext *ctx, void *opaque) 1458 { 1459 NBDExport *exp = opaque; 1460 NBDClient *client; 1461 1462 trace_nbd_blk_aio_attached(exp->name, ctx); 1463 1464 exp->common.ctx = ctx; 1465 1466 QTAILQ_FOREACH(client, &exp->clients, next) { 1467 qio_channel_attach_aio_context(client->ioc, ctx); 1468 if (client->recv_coroutine) { 1469 aio_co_schedule(ctx, client->recv_coroutine); 1470 } 1471 if (client->send_coroutine) { 1472 aio_co_schedule(ctx, client->send_coroutine); 1473 } 1474 } 1475 } 1476 1477 static void blk_aio_detach(void *opaque) 1478 { 1479 NBDExport *exp = opaque; 1480 NBDClient *client; 1481 1482 trace_nbd_blk_aio_detach(exp->name, exp->common.ctx); 1483 1484 QTAILQ_FOREACH(client, &exp->clients, next) { 1485 qio_channel_detach_aio_context(client->ioc); 1486 } 1487 1488 exp->common.ctx = NULL; 1489 } 1490 1491 static void nbd_eject_notifier(Notifier *n, void *data) 1492 { 1493 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1494 1495 blk_exp_request_shutdown(&exp->common); 1496 } 1497 1498 void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk) 1499 { 1500 NBDExport *nbd_exp = container_of(exp, NBDExport, common); 1501 assert(exp->drv == &blk_exp_nbd); 1502 assert(nbd_exp->eject_notifier_blk == NULL); 1503 1504 blk_ref(blk); 1505 nbd_exp->eject_notifier_blk = blk; 1506 nbd_exp->eject_notifier.notify = nbd_eject_notifier; 1507 blk_add_remove_bs_notifier(blk, &nbd_exp->eject_notifier); 1508 } 1509 1510 static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args, 1511 Error **errp) 1512 { 1513 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1514 BlockExportOptionsNbd *arg = &exp_args->u.nbd; 1515 BlockBackend *blk = blk_exp->blk; 1516 int64_t size; 1517 uint64_t perm, shared_perm; 1518 bool readonly = !exp_args->writable; 1519 bool shared = !exp_args->writable; 1520 int ret; 1521 1522 assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD); 1523 1524 if (!nbd_server_is_running()) { 1525 error_setg(errp, "NBD server not running"); 1526 return -EINVAL; 1527 } 1528 1529 if (!arg->has_name) { 1530 arg->name = exp_args->node_name; 1531 } 1532 1533 if (strlen(arg->name) > NBD_MAX_STRING_SIZE) { 1534 error_setg(errp, "export name '%s' too long", arg->name); 1535 return -EINVAL; 1536 } 1537 1538 if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) { 1539 error_setg(errp, "description '%s' too long", arg->description); 1540 return -EINVAL; 1541 } 1542 1543 if (nbd_export_find(arg->name)) { 1544 error_setg(errp, "NBD server already has export named '%s'", arg->name); 1545 return -EEXIST; 1546 } 1547 1548 size = blk_getlength(blk); 1549 if (size < 0) { 1550 error_setg_errno(errp, -size, 1551 "Failed to determine the NBD export's length"); 1552 return size; 1553 } 1554 1555 /* Don't allow resize while the NBD server is running, otherwise we don't 1556 * care what happens with the node. */ 1557 blk_get_perm(blk, &perm, &shared_perm); 1558 ret = blk_set_perm(blk, perm, shared_perm & ~BLK_PERM_RESIZE, errp); 1559 if (ret < 0) { 1560 return ret; 1561 } 1562 1563 blk_set_allow_aio_context_change(blk, true); 1564 1565 QTAILQ_INIT(&exp->clients); 1566 exp->name = g_strdup(arg->name); 1567 exp->description = g_strdup(arg->description); 1568 exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH | 1569 NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE); 1570 if (readonly) { 1571 exp->nbdflags |= NBD_FLAG_READ_ONLY; 1572 if (shared) { 1573 exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN; 1574 } 1575 } else { 1576 exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES | 1577 NBD_FLAG_SEND_FAST_ZERO); 1578 } 1579 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); 1580 1581 if (arg->bitmap) { 1582 BlockDriverState *bs = blk_bs(blk); 1583 BdrvDirtyBitmap *bm = NULL; 1584 1585 while (bs) { 1586 bm = bdrv_find_dirty_bitmap(bs, arg->bitmap); 1587 if (bm != NULL) { 1588 break; 1589 } 1590 1591 bs = bdrv_filter_or_cow_bs(bs); 1592 } 1593 1594 if (bm == NULL) { 1595 ret = -ENOENT; 1596 error_setg(errp, "Bitmap '%s' is not found", arg->bitmap); 1597 goto fail; 1598 } 1599 1600 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) { 1601 ret = -EINVAL; 1602 goto fail; 1603 } 1604 1605 if (readonly && bdrv_is_writable(bs) && 1606 bdrv_dirty_bitmap_enabled(bm)) { 1607 ret = -EINVAL; 1608 error_setg(errp, 1609 "Enabled bitmap '%s' incompatible with readonly export", 1610 arg->bitmap); 1611 goto fail; 1612 } 1613 1614 bdrv_dirty_bitmap_set_busy(bm, true); 1615 exp->export_bitmap = bm; 1616 assert(strlen(arg->bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE); 1617 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s", 1618 arg->bitmap); 1619 assert(strlen(exp->export_bitmap_context) < NBD_MAX_STRING_SIZE); 1620 } 1621 1622 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1623 1624 QTAILQ_INSERT_TAIL(&exports, exp, next); 1625 1626 return 0; 1627 1628 fail: 1629 g_free(exp->name); 1630 g_free(exp->description); 1631 return ret; 1632 } 1633 1634 NBDExport *nbd_export_find(const char *name) 1635 { 1636 NBDExport *exp; 1637 QTAILQ_FOREACH(exp, &exports, next) { 1638 if (strcmp(name, exp->name) == 0) { 1639 return exp; 1640 } 1641 } 1642 1643 return NULL; 1644 } 1645 1646 AioContext * 1647 nbd_export_aio_context(NBDExport *exp) 1648 { 1649 return exp->common.ctx; 1650 } 1651 1652 static void nbd_export_request_shutdown(BlockExport *blk_exp) 1653 { 1654 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1655 NBDClient *client, *next; 1656 1657 blk_exp_ref(&exp->common); 1658 /* 1659 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a 1660 * close mode that stops advertising the export to new clients but 1661 * still permits existing clients to run to completion? Because of 1662 * that possibility, nbd_export_close() can be called more than 1663 * once on an export. 1664 */ 1665 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1666 client_close(client, true); 1667 } 1668 if (exp->name) { 1669 g_free(exp->name); 1670 exp->name = NULL; 1671 QTAILQ_REMOVE(&exports, exp, next); 1672 } 1673 blk_exp_unref(&exp->common); 1674 } 1675 1676 static void nbd_export_delete(BlockExport *blk_exp) 1677 { 1678 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1679 1680 assert(exp->name == NULL); 1681 assert(QTAILQ_EMPTY(&exp->clients)); 1682 1683 g_free(exp->description); 1684 exp->description = NULL; 1685 1686 if (exp->common.blk) { 1687 if (exp->eject_notifier_blk) { 1688 notifier_remove(&exp->eject_notifier); 1689 blk_unref(exp->eject_notifier_blk); 1690 } 1691 blk_remove_aio_context_notifier(exp->common.blk, blk_aio_attached, 1692 blk_aio_detach, exp); 1693 } 1694 1695 if (exp->export_bitmap) { 1696 bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false); 1697 g_free(exp->export_bitmap_context); 1698 } 1699 } 1700 1701 const BlockExportDriver blk_exp_nbd = { 1702 .type = BLOCK_EXPORT_TYPE_NBD, 1703 .instance_size = sizeof(NBDExport), 1704 .create = nbd_export_create, 1705 .delete = nbd_export_delete, 1706 .request_shutdown = nbd_export_request_shutdown, 1707 }; 1708 1709 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1710 unsigned niov, Error **errp) 1711 { 1712 int ret; 1713 1714 g_assert(qemu_in_coroutine()); 1715 qemu_co_mutex_lock(&client->send_lock); 1716 client->send_coroutine = qemu_coroutine_self(); 1717 1718 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1719 1720 client->send_coroutine = NULL; 1721 qemu_co_mutex_unlock(&client->send_lock); 1722 1723 return ret; 1724 } 1725 1726 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1727 uint64_t handle) 1728 { 1729 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1730 stl_be_p(&reply->error, error); 1731 stq_be_p(&reply->handle, handle); 1732 } 1733 1734 static int nbd_co_send_simple_reply(NBDClient *client, 1735 uint64_t handle, 1736 uint32_t error, 1737 void *data, 1738 size_t len, 1739 Error **errp) 1740 { 1741 NBDSimpleReply reply; 1742 int nbd_err = system_errno_to_nbd_errno(error); 1743 struct iovec iov[] = { 1744 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1745 {.iov_base = data, .iov_len = len} 1746 }; 1747 1748 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1749 len); 1750 set_be_simple_reply(&reply, nbd_err, handle); 1751 1752 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1753 } 1754 1755 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1756 uint16_t type, uint64_t handle, uint32_t length) 1757 { 1758 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1759 stw_be_p(&chunk->flags, flags); 1760 stw_be_p(&chunk->type, type); 1761 stq_be_p(&chunk->handle, handle); 1762 stl_be_p(&chunk->length, length); 1763 } 1764 1765 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1766 uint64_t handle, 1767 Error **errp) 1768 { 1769 NBDStructuredReplyChunk chunk; 1770 struct iovec iov[] = { 1771 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1772 }; 1773 1774 trace_nbd_co_send_structured_done(handle); 1775 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1776 1777 return nbd_co_send_iov(client, iov, 1, errp); 1778 } 1779 1780 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1781 uint64_t handle, 1782 uint64_t offset, 1783 void *data, 1784 size_t size, 1785 bool final, 1786 Error **errp) 1787 { 1788 NBDStructuredReadData chunk; 1789 struct iovec iov[] = { 1790 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1791 {.iov_base = data, .iov_len = size} 1792 }; 1793 1794 assert(size); 1795 trace_nbd_co_send_structured_read(handle, offset, data, size); 1796 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1797 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1798 sizeof(chunk) - sizeof(chunk.h) + size); 1799 stq_be_p(&chunk.offset, offset); 1800 1801 return nbd_co_send_iov(client, iov, 2, errp); 1802 } 1803 1804 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1805 uint64_t handle, 1806 uint32_t error, 1807 const char *msg, 1808 Error **errp) 1809 { 1810 NBDStructuredError chunk; 1811 int nbd_err = system_errno_to_nbd_errno(error); 1812 struct iovec iov[] = { 1813 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1814 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1815 }; 1816 1817 assert(nbd_err); 1818 trace_nbd_co_send_structured_error(handle, nbd_err, 1819 nbd_err_lookup(nbd_err), msg ? msg : ""); 1820 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1821 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1822 stl_be_p(&chunk.error, nbd_err); 1823 stw_be_p(&chunk.message_length, iov[1].iov_len); 1824 1825 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1826 } 1827 1828 /* Do a sparse read and send the structured reply to the client. 1829 * Returns -errno if sending fails. bdrv_block_status_above() failure is 1830 * reported to the client, at which point this function succeeds. 1831 */ 1832 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1833 uint64_t handle, 1834 uint64_t offset, 1835 uint8_t *data, 1836 size_t size, 1837 Error **errp) 1838 { 1839 int ret = 0; 1840 NBDExport *exp = client->exp; 1841 size_t progress = 0; 1842 1843 while (progress < size) { 1844 int64_t pnum; 1845 int status = bdrv_block_status_above(blk_bs(exp->common.blk), NULL, 1846 offset + progress, 1847 size - progress, &pnum, NULL, 1848 NULL); 1849 bool final; 1850 1851 if (status < 0) { 1852 char *msg = g_strdup_printf("unable to check for holes: %s", 1853 strerror(-status)); 1854 1855 ret = nbd_co_send_structured_error(client, handle, -status, msg, 1856 errp); 1857 g_free(msg); 1858 return ret; 1859 } 1860 assert(pnum && pnum <= size - progress); 1861 final = progress + pnum == size; 1862 if (status & BDRV_BLOCK_ZERO) { 1863 NBDStructuredReadHole chunk; 1864 struct iovec iov[] = { 1865 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1866 }; 1867 1868 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1869 pnum); 1870 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1871 NBD_REPLY_TYPE_OFFSET_HOLE, 1872 handle, sizeof(chunk) - sizeof(chunk.h)); 1873 stq_be_p(&chunk.offset, offset + progress); 1874 stl_be_p(&chunk.length, pnum); 1875 ret = nbd_co_send_iov(client, iov, 1, errp); 1876 } else { 1877 ret = blk_pread(exp->common.blk, offset + progress, 1878 data + progress, pnum); 1879 if (ret < 0) { 1880 error_setg_errno(errp, -ret, "reading from file failed"); 1881 break; 1882 } 1883 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1884 data + progress, pnum, final, 1885 errp); 1886 } 1887 1888 if (ret < 0) { 1889 break; 1890 } 1891 progress += pnum; 1892 } 1893 return ret; 1894 } 1895 1896 typedef struct NBDExtentArray { 1897 NBDExtent *extents; 1898 unsigned int nb_alloc; 1899 unsigned int count; 1900 uint64_t total_length; 1901 bool can_add; 1902 bool converted_to_be; 1903 } NBDExtentArray; 1904 1905 static NBDExtentArray *nbd_extent_array_new(unsigned int nb_alloc) 1906 { 1907 NBDExtentArray *ea = g_new0(NBDExtentArray, 1); 1908 1909 ea->nb_alloc = nb_alloc; 1910 ea->extents = g_new(NBDExtent, nb_alloc); 1911 ea->can_add = true; 1912 1913 return ea; 1914 } 1915 1916 static void nbd_extent_array_free(NBDExtentArray *ea) 1917 { 1918 g_free(ea->extents); 1919 g_free(ea); 1920 } 1921 G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray, nbd_extent_array_free); 1922 1923 /* Further modifications of the array after conversion are abandoned */ 1924 static void nbd_extent_array_convert_to_be(NBDExtentArray *ea) 1925 { 1926 int i; 1927 1928 assert(!ea->converted_to_be); 1929 ea->can_add = false; 1930 ea->converted_to_be = true; 1931 1932 for (i = 0; i < ea->count; i++) { 1933 ea->extents[i].flags = cpu_to_be32(ea->extents[i].flags); 1934 ea->extents[i].length = cpu_to_be32(ea->extents[i].length); 1935 } 1936 } 1937 1938 /* 1939 * Add extent to NBDExtentArray. If extent can't be added (no available space), 1940 * return -1. 1941 * For safety, when returning -1 for the first time, .can_add is set to false, 1942 * further call to nbd_extent_array_add() will crash. 1943 * (to avoid the situation, when after failing to add an extent (returned -1), 1944 * user miss this failure and add another extent, which is successfully added 1945 * (array is full, but new extent may be squashed into the last one), then we 1946 * have invalid array with skipped extent) 1947 */ 1948 static int nbd_extent_array_add(NBDExtentArray *ea, 1949 uint32_t length, uint32_t flags) 1950 { 1951 assert(ea->can_add); 1952 1953 if (!length) { 1954 return 0; 1955 } 1956 1957 /* Extend previous extent if flags are the same */ 1958 if (ea->count > 0 && flags == ea->extents[ea->count - 1].flags) { 1959 uint64_t sum = (uint64_t)length + ea->extents[ea->count - 1].length; 1960 1961 if (sum <= UINT32_MAX) { 1962 ea->extents[ea->count - 1].length = sum; 1963 ea->total_length += length; 1964 return 0; 1965 } 1966 } 1967 1968 if (ea->count >= ea->nb_alloc) { 1969 ea->can_add = false; 1970 return -1; 1971 } 1972 1973 ea->total_length += length; 1974 ea->extents[ea->count] = (NBDExtent) {.length = length, .flags = flags}; 1975 ea->count++; 1976 1977 return 0; 1978 } 1979 1980 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, 1981 uint64_t bytes, NBDExtentArray *ea) 1982 { 1983 while (bytes) { 1984 uint32_t flags; 1985 int64_t num; 1986 int ret = bdrv_block_status_above(bs, NULL, offset, bytes, &num, 1987 NULL, NULL); 1988 1989 if (ret < 0) { 1990 return ret; 1991 } 1992 1993 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) | 1994 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 1995 1996 if (nbd_extent_array_add(ea, num, flags) < 0) { 1997 return 0; 1998 } 1999 2000 offset += num; 2001 bytes -= num; 2002 } 2003 2004 return 0; 2005 } 2006 2007 /* 2008 * nbd_co_send_extents 2009 * 2010 * @ea is converted to BE by the function 2011 * @last controls whether NBD_REPLY_FLAG_DONE is sent. 2012 */ 2013 static int nbd_co_send_extents(NBDClient *client, uint64_t handle, 2014 NBDExtentArray *ea, 2015 bool last, uint32_t context_id, Error **errp) 2016 { 2017 NBDStructuredMeta chunk; 2018 struct iovec iov[] = { 2019 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 2020 {.iov_base = ea->extents, .iov_len = ea->count * sizeof(ea->extents[0])} 2021 }; 2022 2023 nbd_extent_array_convert_to_be(ea); 2024 2025 trace_nbd_co_send_extents(handle, ea->count, context_id, ea->total_length, 2026 last); 2027 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0, 2028 NBD_REPLY_TYPE_BLOCK_STATUS, 2029 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 2030 stl_be_p(&chunk.context_id, context_id); 2031 2032 return nbd_co_send_iov(client, iov, 2, errp); 2033 } 2034 2035 /* Get block status from the exported device and send it to the client */ 2036 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, 2037 BlockDriverState *bs, uint64_t offset, 2038 uint32_t length, bool dont_fragment, 2039 bool last, uint32_t context_id, 2040 Error **errp) 2041 { 2042 int ret; 2043 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2044 g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents); 2045 2046 ret = blockstatus_to_extents(bs, offset, length, ea); 2047 if (ret < 0) { 2048 return nbd_co_send_structured_error( 2049 client, handle, -ret, "can't get block status", errp); 2050 } 2051 2052 return nbd_co_send_extents(client, handle, ea, last, context_id, errp); 2053 } 2054 2055 /* Populate @ea from a dirty bitmap. */ 2056 static void bitmap_to_extents(BdrvDirtyBitmap *bitmap, 2057 uint64_t offset, uint64_t length, 2058 NBDExtentArray *es) 2059 { 2060 int64_t start, dirty_start, dirty_count; 2061 int64_t end = offset + length; 2062 bool full = false; 2063 2064 bdrv_dirty_bitmap_lock(bitmap); 2065 2066 for (start = offset; 2067 bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, INT32_MAX, 2068 &dirty_start, &dirty_count); 2069 start = dirty_start + dirty_count) 2070 { 2071 if ((nbd_extent_array_add(es, dirty_start - start, 0) < 0) || 2072 (nbd_extent_array_add(es, dirty_count, NBD_STATE_DIRTY) < 0)) 2073 { 2074 full = true; 2075 break; 2076 } 2077 } 2078 2079 if (!full) { 2080 /* last non dirty extent */ 2081 nbd_extent_array_add(es, end - start, 0); 2082 } 2083 2084 bdrv_dirty_bitmap_unlock(bitmap); 2085 } 2086 2087 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, 2088 BdrvDirtyBitmap *bitmap, uint64_t offset, 2089 uint32_t length, bool dont_fragment, bool last, 2090 uint32_t context_id, Error **errp) 2091 { 2092 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2093 g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents); 2094 2095 bitmap_to_extents(bitmap, offset, length, ea); 2096 2097 return nbd_co_send_extents(client, handle, ea, last, context_id, errp); 2098 } 2099 2100 /* nbd_co_receive_request 2101 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2102 * connection right away, and any other negative value to report an error to 2103 * the client (although the caller may still need to disconnect after reporting 2104 * the error). 2105 */ 2106 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 2107 Error **errp) 2108 { 2109 NBDClient *client = req->client; 2110 int valid_flags; 2111 2112 g_assert(qemu_in_coroutine()); 2113 assert(client->recv_coroutine == qemu_coroutine_self()); 2114 if (nbd_receive_request(client->ioc, request, errp) < 0) { 2115 return -EIO; 2116 } 2117 2118 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 2119 nbd_cmd_lookup(request->type)); 2120 2121 if (request->type != NBD_CMD_WRITE) { 2122 /* No payload, we are ready to read the next request. */ 2123 req->complete = true; 2124 } 2125 2126 if (request->type == NBD_CMD_DISC) { 2127 /* Special case: we're going to disconnect without a reply, 2128 * whether or not flags, from, or len are bogus */ 2129 return -EIO; 2130 } 2131 2132 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE || 2133 request->type == NBD_CMD_CACHE) 2134 { 2135 if (request->len > NBD_MAX_BUFFER_SIZE) { 2136 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 2137 request->len, NBD_MAX_BUFFER_SIZE); 2138 return -EINVAL; 2139 } 2140 2141 if (request->type != NBD_CMD_CACHE) { 2142 req->data = blk_try_blockalign(client->exp->common.blk, 2143 request->len); 2144 if (req->data == NULL) { 2145 error_setg(errp, "No memory"); 2146 return -ENOMEM; 2147 } 2148 } 2149 } 2150 2151 if (request->type == NBD_CMD_WRITE) { 2152 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data", 2153 errp) < 0) 2154 { 2155 return -EIO; 2156 } 2157 req->complete = true; 2158 2159 trace_nbd_co_receive_request_payload_received(request->handle, 2160 request->len); 2161 } 2162 2163 /* Sanity checks. */ 2164 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 2165 (request->type == NBD_CMD_WRITE || 2166 request->type == NBD_CMD_WRITE_ZEROES || 2167 request->type == NBD_CMD_TRIM)) { 2168 error_setg(errp, "Export is read-only"); 2169 return -EROFS; 2170 } 2171 if (request->from > client->exp->size || 2172 request->len > client->exp->size - request->from) { 2173 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 2174 ", Size: %" PRIu64, request->from, request->len, 2175 client->exp->size); 2176 return (request->type == NBD_CMD_WRITE || 2177 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2178 } 2179 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len, 2180 client->check_align)) { 2181 /* 2182 * The block layer gracefully handles unaligned requests, but 2183 * it's still worth tracing client non-compliance 2184 */ 2185 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type), 2186 request->from, 2187 request->len, 2188 client->check_align); 2189 } 2190 valid_flags = NBD_CMD_FLAG_FUA; 2191 if (request->type == NBD_CMD_READ && client->structured_reply) { 2192 valid_flags |= NBD_CMD_FLAG_DF; 2193 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 2194 valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO; 2195 } else if (request->type == NBD_CMD_BLOCK_STATUS) { 2196 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2197 } 2198 if (request->flags & ~valid_flags) { 2199 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2200 nbd_cmd_lookup(request->type), request->flags); 2201 return -EINVAL; 2202 } 2203 2204 return 0; 2205 } 2206 2207 /* Send simple reply without a payload, or a structured error 2208 * @error_msg is ignored if @ret >= 0 2209 * Returns 0 if connection is still live, -errno on failure to talk to client 2210 */ 2211 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2212 uint64_t handle, 2213 int ret, 2214 const char *error_msg, 2215 Error **errp) 2216 { 2217 if (client->structured_reply && ret < 0) { 2218 return nbd_co_send_structured_error(client, handle, -ret, error_msg, 2219 errp); 2220 } else { 2221 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0, 2222 NULL, 0, errp); 2223 } 2224 } 2225 2226 /* Handle NBD_CMD_READ request. 2227 * Return -errno if sending fails. Other errors are reported directly to the 2228 * client as an error reply. */ 2229 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2230 uint8_t *data, Error **errp) 2231 { 2232 int ret; 2233 NBDExport *exp = client->exp; 2234 2235 assert(request->type == NBD_CMD_READ); 2236 2237 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2238 if (request->flags & NBD_CMD_FLAG_FUA) { 2239 ret = blk_co_flush(exp->common.blk); 2240 if (ret < 0) { 2241 return nbd_send_generic_reply(client, request->handle, ret, 2242 "flush failed", errp); 2243 } 2244 } 2245 2246 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) && 2247 request->len) 2248 { 2249 return nbd_co_send_sparse_read(client, request->handle, request->from, 2250 data, request->len, errp); 2251 } 2252 2253 ret = blk_pread(exp->common.blk, request->from, data, request->len); 2254 if (ret < 0) { 2255 return nbd_send_generic_reply(client, request->handle, ret, 2256 "reading from file failed", errp); 2257 } 2258 2259 if (client->structured_reply) { 2260 if (request->len) { 2261 return nbd_co_send_structured_read(client, request->handle, 2262 request->from, data, 2263 request->len, true, errp); 2264 } else { 2265 return nbd_co_send_structured_done(client, request->handle, errp); 2266 } 2267 } else { 2268 return nbd_co_send_simple_reply(client, request->handle, 0, 2269 data, request->len, errp); 2270 } 2271 } 2272 2273 /* 2274 * nbd_do_cmd_cache 2275 * 2276 * Handle NBD_CMD_CACHE request. 2277 * Return -errno if sending fails. Other errors are reported directly to the 2278 * client as an error reply. 2279 */ 2280 static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request, 2281 Error **errp) 2282 { 2283 int ret; 2284 NBDExport *exp = client->exp; 2285 2286 assert(request->type == NBD_CMD_CACHE); 2287 2288 ret = blk_co_preadv(exp->common.blk, request->from, request->len, 2289 NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH); 2290 2291 return nbd_send_generic_reply(client, request->handle, ret, 2292 "caching data failed", errp); 2293 } 2294 2295 /* Handle NBD request. 2296 * Return -errno if sending fails. Other errors are reported directly to the 2297 * client as an error reply. */ 2298 static coroutine_fn int nbd_handle_request(NBDClient *client, 2299 NBDRequest *request, 2300 uint8_t *data, Error **errp) 2301 { 2302 int ret; 2303 int flags; 2304 NBDExport *exp = client->exp; 2305 char *msg; 2306 2307 switch (request->type) { 2308 case NBD_CMD_CACHE: 2309 return nbd_do_cmd_cache(client, request, errp); 2310 2311 case NBD_CMD_READ: 2312 return nbd_do_cmd_read(client, request, data, errp); 2313 2314 case NBD_CMD_WRITE: 2315 flags = 0; 2316 if (request->flags & NBD_CMD_FLAG_FUA) { 2317 flags |= BDRV_REQ_FUA; 2318 } 2319 ret = blk_pwrite(exp->common.blk, request->from, data, request->len, 2320 flags); 2321 return nbd_send_generic_reply(client, request->handle, ret, 2322 "writing to file failed", errp); 2323 2324 case NBD_CMD_WRITE_ZEROES: 2325 flags = 0; 2326 if (request->flags & NBD_CMD_FLAG_FUA) { 2327 flags |= BDRV_REQ_FUA; 2328 } 2329 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2330 flags |= BDRV_REQ_MAY_UNMAP; 2331 } 2332 if (request->flags & NBD_CMD_FLAG_FAST_ZERO) { 2333 flags |= BDRV_REQ_NO_FALLBACK; 2334 } 2335 ret = 0; 2336 /* FIXME simplify this when blk_pwrite_zeroes switches to 64-bit */ 2337 while (ret >= 0 && request->len) { 2338 int align = client->check_align ?: 1; 2339 int len = MIN(request->len, QEMU_ALIGN_DOWN(BDRV_REQUEST_MAX_BYTES, 2340 align)); 2341 ret = blk_pwrite_zeroes(exp->common.blk, request->from, len, flags); 2342 request->len -= len; 2343 request->from += len; 2344 } 2345 return nbd_send_generic_reply(client, request->handle, ret, 2346 "writing to file failed", errp); 2347 2348 case NBD_CMD_DISC: 2349 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2350 abort(); 2351 2352 case NBD_CMD_FLUSH: 2353 ret = blk_co_flush(exp->common.blk); 2354 return nbd_send_generic_reply(client, request->handle, ret, 2355 "flush failed", errp); 2356 2357 case NBD_CMD_TRIM: 2358 ret = 0; 2359 /* FIXME simplify this when blk_co_pdiscard switches to 64-bit */ 2360 while (ret >= 0 && request->len) { 2361 int align = client->check_align ?: 1; 2362 int len = MIN(request->len, QEMU_ALIGN_DOWN(BDRV_REQUEST_MAX_BYTES, 2363 align)); 2364 ret = blk_co_pdiscard(exp->common.blk, request->from, len); 2365 request->len -= len; 2366 request->from += len; 2367 } 2368 if (ret >= 0 && request->flags & NBD_CMD_FLAG_FUA) { 2369 ret = blk_co_flush(exp->common.blk); 2370 } 2371 return nbd_send_generic_reply(client, request->handle, ret, 2372 "discard failed", errp); 2373 2374 case NBD_CMD_BLOCK_STATUS: 2375 if (!request->len) { 2376 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2377 "need non-zero length", errp); 2378 } 2379 if (client->export_meta.valid && 2380 (client->export_meta.base_allocation || 2381 client->export_meta.bitmap)) 2382 { 2383 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2384 2385 if (client->export_meta.base_allocation) { 2386 ret = nbd_co_send_block_status(client, request->handle, 2387 blk_bs(exp->common.blk), 2388 request->from, 2389 request->len, dont_fragment, 2390 !client->export_meta.bitmap, 2391 NBD_META_ID_BASE_ALLOCATION, 2392 errp); 2393 if (ret < 0) { 2394 return ret; 2395 } 2396 } 2397 2398 if (client->export_meta.bitmap) { 2399 ret = nbd_co_send_bitmap(client, request->handle, 2400 client->exp->export_bitmap, 2401 request->from, request->len, 2402 dont_fragment, 2403 true, NBD_META_ID_DIRTY_BITMAP, errp); 2404 if (ret < 0) { 2405 return ret; 2406 } 2407 } 2408 2409 return 0; 2410 } else { 2411 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2412 "CMD_BLOCK_STATUS not negotiated", 2413 errp); 2414 } 2415 2416 default: 2417 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 2418 request->type); 2419 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg, 2420 errp); 2421 g_free(msg); 2422 return ret; 2423 } 2424 } 2425 2426 /* Owns a reference to the NBDClient passed as opaque. */ 2427 static coroutine_fn void nbd_trip(void *opaque) 2428 { 2429 NBDClient *client = opaque; 2430 NBDRequestData *req; 2431 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 2432 int ret; 2433 Error *local_err = NULL; 2434 2435 trace_nbd_trip(); 2436 if (client->closing) { 2437 nbd_client_put(client); 2438 return; 2439 } 2440 2441 req = nbd_request_get(client); 2442 ret = nbd_co_receive_request(req, &request, &local_err); 2443 client->recv_coroutine = NULL; 2444 2445 if (client->closing) { 2446 /* 2447 * The client may be closed when we are blocked in 2448 * nbd_co_receive_request() 2449 */ 2450 goto done; 2451 } 2452 2453 nbd_client_receive_next_request(client); 2454 if (ret == -EIO) { 2455 goto disconnect; 2456 } 2457 2458 if (ret < 0) { 2459 /* It wans't -EIO, so, according to nbd_co_receive_request() 2460 * semantics, we should return the error to the client. */ 2461 Error *export_err = local_err; 2462 2463 local_err = NULL; 2464 ret = nbd_send_generic_reply(client, request.handle, -EINVAL, 2465 error_get_pretty(export_err), &local_err); 2466 error_free(export_err); 2467 } else { 2468 ret = nbd_handle_request(client, &request, req->data, &local_err); 2469 } 2470 if (ret < 0) { 2471 error_prepend(&local_err, "Failed to send reply: "); 2472 goto disconnect; 2473 } 2474 2475 /* We must disconnect after NBD_CMD_WRITE if we did not 2476 * read the payload. 2477 */ 2478 if (!req->complete) { 2479 error_setg(&local_err, "Request handling failed in intermediate state"); 2480 goto disconnect; 2481 } 2482 2483 done: 2484 nbd_request_put(req); 2485 nbd_client_put(client); 2486 return; 2487 2488 disconnect: 2489 if (local_err) { 2490 error_reportf_err(local_err, "Disconnect client, due to: "); 2491 } 2492 nbd_request_put(req); 2493 client_close(client, true); 2494 nbd_client_put(client); 2495 } 2496 2497 static void nbd_client_receive_next_request(NBDClient *client) 2498 { 2499 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 2500 nbd_client_get(client); 2501 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 2502 aio_co_schedule(client->exp->common.ctx, client->recv_coroutine); 2503 } 2504 } 2505 2506 static coroutine_fn void nbd_co_client_start(void *opaque) 2507 { 2508 NBDClient *client = opaque; 2509 Error *local_err = NULL; 2510 2511 qemu_co_mutex_init(&client->send_lock); 2512 2513 if (nbd_negotiate(client, &local_err)) { 2514 if (local_err) { 2515 error_report_err(local_err); 2516 } 2517 client_close(client, false); 2518 return; 2519 } 2520 2521 nbd_client_receive_next_request(client); 2522 } 2523 2524 /* 2525 * Create a new client listener using the given channel @sioc. 2526 * Begin servicing it in a coroutine. When the connection closes, call 2527 * @close_fn with an indication of whether the client completed negotiation. 2528 */ 2529 void nbd_client_new(QIOChannelSocket *sioc, 2530 QCryptoTLSCreds *tlscreds, 2531 const char *tlsauthz, 2532 void (*close_fn)(NBDClient *, bool)) 2533 { 2534 NBDClient *client; 2535 Coroutine *co; 2536 2537 client = g_new0(NBDClient, 1); 2538 client->refcount = 1; 2539 client->tlscreds = tlscreds; 2540 if (tlscreds) { 2541 object_ref(OBJECT(client->tlscreds)); 2542 } 2543 client->tlsauthz = g_strdup(tlsauthz); 2544 client->sioc = sioc; 2545 object_ref(OBJECT(client->sioc)); 2546 client->ioc = QIO_CHANNEL(sioc); 2547 object_ref(OBJECT(client->ioc)); 2548 client->close_fn = close_fn; 2549 2550 co = qemu_coroutine_create(nbd_co_client_start, client); 2551 qemu_coroutine_enter(co); 2552 } 2553