1 /* 2 * Copyright Red Hat 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/block_int.h" 23 #include "block/export.h" 24 #include "block/dirty-bitmap.h" 25 #include "qapi/error.h" 26 #include "qemu/queue.h" 27 #include "trace.h" 28 #include "nbd-internal.h" 29 #include "qemu/units.h" 30 #include "qemu/memalign.h" 31 32 #define NBD_META_ID_BASE_ALLOCATION 0 33 #define NBD_META_ID_ALLOCATION_DEPTH 1 34 /* Dirty bitmaps use 'NBD_META_ID_DIRTY_BITMAP + i', so keep this id last. */ 35 #define NBD_META_ID_DIRTY_BITMAP 2 36 37 /* 38 * NBD_MAX_BLOCK_STATUS_EXTENTS: 1 MiB of extents data. An empirical 39 * constant. If an increase is needed, note that the NBD protocol 40 * recommends no larger than 32 mb, so that the client won't consider 41 * the reply as a denial of service attack. 42 */ 43 #define NBD_MAX_BLOCK_STATUS_EXTENTS (1 * MiB / 8) 44 45 static int system_errno_to_nbd_errno(int err) 46 { 47 switch (err) { 48 case 0: 49 return NBD_SUCCESS; 50 case EPERM: 51 case EROFS: 52 return NBD_EPERM; 53 case EIO: 54 return NBD_EIO; 55 case ENOMEM: 56 return NBD_ENOMEM; 57 #ifdef EDQUOT 58 case EDQUOT: 59 #endif 60 case EFBIG: 61 case ENOSPC: 62 return NBD_ENOSPC; 63 case EOVERFLOW: 64 return NBD_EOVERFLOW; 65 case ENOTSUP: 66 #if ENOTSUP != EOPNOTSUPP 67 case EOPNOTSUPP: 68 #endif 69 return NBD_ENOTSUP; 70 case ESHUTDOWN: 71 return NBD_ESHUTDOWN; 72 case EINVAL: 73 default: 74 return NBD_EINVAL; 75 } 76 } 77 78 /* Definitions for opaque data types */ 79 80 typedef struct NBDRequestData NBDRequestData; 81 82 struct NBDRequestData { 83 NBDClient *client; 84 uint8_t *data; 85 bool complete; 86 }; 87 88 struct NBDExport { 89 BlockExport common; 90 91 char *name; 92 char *description; 93 uint64_t size; 94 uint16_t nbdflags; 95 QTAILQ_HEAD(, NBDClient) clients; 96 QTAILQ_ENTRY(NBDExport) next; 97 98 BlockBackend *eject_notifier_blk; 99 Notifier eject_notifier; 100 101 bool allocation_depth; 102 BdrvDirtyBitmap **export_bitmaps; 103 size_t nr_export_bitmaps; 104 }; 105 106 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); 107 108 /* 109 * NBDMetaContexts represents a list of meta contexts in use, 110 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for 111 * NBD_OPT_LIST_META_CONTEXT. 112 */ 113 struct NBDMetaContexts { 114 const NBDExport *exp; /* associated export */ 115 size_t count; /* number of negotiated contexts */ 116 bool base_allocation; /* export base:allocation context (block status) */ 117 bool allocation_depth; /* export qemu:allocation-depth */ 118 bool *bitmaps; /* 119 * export qemu:dirty-bitmap:<export bitmap name>, 120 * sized by exp->nr_export_bitmaps 121 */ 122 }; 123 124 struct NBDClient { 125 int refcount; /* atomic */ 126 void (*close_fn)(NBDClient *client, bool negotiated); 127 void *owner; 128 129 QemuMutex lock; 130 131 NBDExport *exp; 132 QCryptoTLSCreds *tlscreds; 133 char *tlsauthz; 134 uint32_t handshake_max_secs; 135 QIOChannelSocket *sioc; /* The underlying data channel */ 136 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ 137 138 Coroutine *recv_coroutine; /* protected by lock */ 139 140 CoMutex send_lock; 141 Coroutine *send_coroutine; 142 143 bool read_yielding; /* protected by lock */ 144 bool quiescing; /* protected by lock */ 145 146 QTAILQ_ENTRY(NBDClient) next; 147 int nb_requests; /* protected by lock */ 148 bool closing; /* protected by lock */ 149 150 uint32_t check_align; /* If non-zero, check for aligned client requests */ 151 152 NBDMode mode; 153 NBDMetaContexts contexts; /* Negotiated meta contexts */ 154 155 uint32_t opt; /* Current option being negotiated */ 156 uint32_t optlen; /* remaining length of data in ioc for the option being 157 negotiated now */ 158 }; 159 160 static void nbd_client_receive_next_request(NBDClient *client); 161 162 /* Basic flow for negotiation 163 164 Server Client 165 Negotiate 166 167 or 168 169 Server Client 170 Negotiate #1 171 Option 172 Negotiate #2 173 174 ---- 175 176 followed by 177 178 Server Client 179 Request 180 Response 181 Request 182 Response 183 ... 184 ... 185 Request (type == 2) 186 187 */ 188 189 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option, 190 uint32_t type, uint32_t length) 191 { 192 stq_be_p(&rep->magic, NBD_REP_MAGIC); 193 stl_be_p(&rep->option, option); 194 stl_be_p(&rep->type, type); 195 stl_be_p(&rep->length, length); 196 } 197 198 /* Send a reply header, including length, but no payload. 199 * Return -errno on error, 0 on success. */ 200 static coroutine_fn int 201 nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type, 202 uint32_t len, Error **errp) 203 { 204 NBDOptionReply rep; 205 206 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt), 207 type, nbd_rep_lookup(type), len); 208 209 assert(len < NBD_MAX_BUFFER_SIZE); 210 211 set_be_option_rep(&rep, client->opt, type, len); 212 return nbd_write(client->ioc, &rep, sizeof(rep), errp); 213 } 214 215 /* Send a reply header with default 0 length. 216 * Return -errno on error, 0 on success. */ 217 static coroutine_fn int 218 nbd_negotiate_send_rep(NBDClient *client, uint32_t type, Error **errp) 219 { 220 return nbd_negotiate_send_rep_len(client, type, 0, errp); 221 } 222 223 /* Send an error reply. 224 * Return -errno on error, 0 on success. */ 225 static coroutine_fn int G_GNUC_PRINTF(4, 0) 226 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, 227 Error **errp, const char *fmt, va_list va) 228 { 229 ERRP_GUARD(); 230 g_autofree char *msg = NULL; 231 int ret; 232 size_t len; 233 234 msg = g_strdup_vprintf(fmt, va); 235 len = strlen(msg); 236 assert(len < NBD_MAX_STRING_SIZE); 237 trace_nbd_negotiate_send_rep_err(msg); 238 ret = nbd_negotiate_send_rep_len(client, type, len, errp); 239 if (ret < 0) { 240 return ret; 241 } 242 if (nbd_write(client->ioc, msg, len, errp) < 0) { 243 error_prepend(errp, "write failed (error message): "); 244 return -EIO; 245 } 246 247 return 0; 248 } 249 250 /* 251 * Return a malloc'd copy of @name suitable for use in an error reply. 252 */ 253 static char * 254 nbd_sanitize_name(const char *name) 255 { 256 if (strnlen(name, 80) < 80) { 257 return g_strdup(name); 258 } 259 /* XXX Should we also try to sanitize any control characters? */ 260 return g_strdup_printf("%.80s...", name); 261 } 262 263 /* Send an error reply. 264 * Return -errno on error, 0 on success. */ 265 static coroutine_fn int G_GNUC_PRINTF(4, 5) 266 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type, 267 Error **errp, const char *fmt, ...) 268 { 269 va_list va; 270 int ret; 271 272 va_start(va, fmt); 273 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 274 va_end(va); 275 return ret; 276 } 277 278 /* Drop remainder of the current option, and send a reply with the 279 * given error type and message. Return -errno on read or write 280 * failure; or 0 if connection is still live. */ 281 static coroutine_fn int G_GNUC_PRINTF(4, 0) 282 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp, 283 const char *fmt, va_list va) 284 { 285 int ret = nbd_drop(client->ioc, client->optlen, errp); 286 287 client->optlen = 0; 288 if (!ret) { 289 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 290 } 291 return ret; 292 } 293 294 static coroutine_fn int G_GNUC_PRINTF(4, 5) 295 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp, 296 const char *fmt, ...) 297 { 298 int ret; 299 va_list va; 300 301 va_start(va, fmt); 302 ret = nbd_opt_vdrop(client, type, errp, fmt, va); 303 va_end(va); 304 305 return ret; 306 } 307 308 static coroutine_fn int G_GNUC_PRINTF(3, 4) 309 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...) 310 { 311 int ret; 312 va_list va; 313 314 va_start(va, fmt); 315 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va); 316 va_end(va); 317 318 return ret; 319 } 320 321 /* Read size bytes from the unparsed payload of the current option. 322 * If @check_nul, require that no NUL bytes appear in buffer. 323 * Return -errno on I/O error, 0 if option was completely handled by 324 * sending a reply about inconsistent lengths, or 1 on success. */ 325 static coroutine_fn int 326 nbd_opt_read(NBDClient *client, void *buffer, size_t size, 327 bool check_nul, Error **errp) 328 { 329 if (size > client->optlen) { 330 return nbd_opt_invalid(client, errp, 331 "Inconsistent lengths in option %s", 332 nbd_opt_lookup(client->opt)); 333 } 334 client->optlen -= size; 335 if (qio_channel_read_all(client->ioc, buffer, size, errp) < 0) { 336 return -EIO; 337 } 338 339 if (check_nul && strnlen(buffer, size) != size) { 340 return nbd_opt_invalid(client, errp, 341 "Unexpected embedded NUL in option %s", 342 nbd_opt_lookup(client->opt)); 343 } 344 return 1; 345 } 346 347 /* Drop size bytes from the unparsed payload of the current option. 348 * Return -errno on I/O error, 0 if option was completely handled by 349 * sending a reply about inconsistent lengths, or 1 on success. */ 350 static coroutine_fn int 351 nbd_opt_skip(NBDClient *client, size_t size, Error **errp) 352 { 353 if (size > client->optlen) { 354 return nbd_opt_invalid(client, errp, 355 "Inconsistent lengths in option %s", 356 nbd_opt_lookup(client->opt)); 357 } 358 client->optlen -= size; 359 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1; 360 } 361 362 /* nbd_opt_read_name 363 * 364 * Read a string with the format: 365 * uint32_t len (<= NBD_MAX_STRING_SIZE) 366 * len bytes string (not 0-terminated) 367 * 368 * On success, @name will be allocated. 369 * If @length is non-null, it will be set to the actual string length. 370 * 371 * Return -errno on I/O error, 0 if option was completely handled by 372 * sending a reply about inconsistent lengths, or 1 on success. 373 */ 374 static coroutine_fn int 375 nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length, 376 Error **errp) 377 { 378 int ret; 379 uint32_t len; 380 g_autofree char *local_name = NULL; 381 382 *name = NULL; 383 ret = nbd_opt_read(client, &len, sizeof(len), false, errp); 384 if (ret <= 0) { 385 return ret; 386 } 387 len = cpu_to_be32(len); 388 389 if (len > NBD_MAX_STRING_SIZE) { 390 return nbd_opt_invalid(client, errp, 391 "Invalid name length: %" PRIu32, len); 392 } 393 394 local_name = g_malloc(len + 1); 395 ret = nbd_opt_read(client, local_name, len, true, errp); 396 if (ret <= 0) { 397 return ret; 398 } 399 local_name[len] = '\0'; 400 401 if (length) { 402 *length = len; 403 } 404 *name = g_steal_pointer(&local_name); 405 406 return 1; 407 } 408 409 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 410 * Return -errno on error, 0 on success. */ 411 static coroutine_fn int 412 nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, Error **errp) 413 { 414 ERRP_GUARD(); 415 size_t name_len, desc_len; 416 uint32_t len; 417 const char *name = exp->name ? exp->name : ""; 418 const char *desc = exp->description ? exp->description : ""; 419 QIOChannel *ioc = client->ioc; 420 int ret; 421 422 trace_nbd_negotiate_send_rep_list(name, desc); 423 name_len = strlen(name); 424 desc_len = strlen(desc); 425 assert(name_len <= NBD_MAX_STRING_SIZE && desc_len <= NBD_MAX_STRING_SIZE); 426 len = name_len + desc_len + sizeof(len); 427 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp); 428 if (ret < 0) { 429 return ret; 430 } 431 432 len = cpu_to_be32(name_len); 433 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 434 error_prepend(errp, "write failed (name length): "); 435 return -EINVAL; 436 } 437 438 if (nbd_write(ioc, name, name_len, errp) < 0) { 439 error_prepend(errp, "write failed (name buffer): "); 440 return -EINVAL; 441 } 442 443 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 444 error_prepend(errp, "write failed (description buffer): "); 445 return -EINVAL; 446 } 447 448 return 0; 449 } 450 451 /* Process the NBD_OPT_LIST command, with a potential series of replies. 452 * Return -errno on error, 0 on success. */ 453 static coroutine_fn int 454 nbd_negotiate_handle_list(NBDClient *client, Error **errp) 455 { 456 NBDExport *exp; 457 assert(client->opt == NBD_OPT_LIST); 458 459 /* For each export, send a NBD_REP_SERVER reply. */ 460 QTAILQ_FOREACH(exp, &exports, next) { 461 if (nbd_negotiate_send_rep_list(client, exp, errp)) { 462 return -EINVAL; 463 } 464 } 465 /* Finish with a NBD_REP_ACK. */ 466 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 467 } 468 469 static coroutine_fn void 470 nbd_check_meta_export(NBDClient *client, NBDExport *exp) 471 { 472 if (exp != client->contexts.exp) { 473 client->contexts.count = 0; 474 } 475 } 476 477 /* Send a reply to NBD_OPT_EXPORT_NAME. 478 * Return -errno on error, 0 on success. */ 479 static coroutine_fn int 480 nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes, 481 Error **errp) 482 { 483 ERRP_GUARD(); 484 g_autofree char *name = NULL; 485 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 486 size_t len; 487 int ret; 488 uint16_t myflags; 489 490 /* Client sends: 491 [20 .. xx] export name (length bytes) 492 Server replies: 493 [ 0 .. 7] size 494 [ 8 .. 9] export flags 495 [10 .. 133] reserved (0) [unless no_zeroes] 496 */ 497 trace_nbd_negotiate_handle_export_name(); 498 if (client->mode >= NBD_MODE_EXTENDED) { 499 error_setg(errp, "Extended headers already negotiated"); 500 return -EINVAL; 501 } 502 if (client->optlen > NBD_MAX_STRING_SIZE) { 503 error_setg(errp, "Bad length received"); 504 return -EINVAL; 505 } 506 name = g_malloc(client->optlen + 1); 507 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) { 508 return -EIO; 509 } 510 name[client->optlen] = '\0'; 511 client->optlen = 0; 512 513 trace_nbd_negotiate_handle_export_name_request(name); 514 515 client->exp = nbd_export_find(name); 516 if (!client->exp) { 517 error_setg(errp, "export not found"); 518 return -EINVAL; 519 } 520 nbd_check_meta_export(client, client->exp); 521 522 myflags = client->exp->nbdflags; 523 if (client->mode >= NBD_MODE_STRUCTURED) { 524 myflags |= NBD_FLAG_SEND_DF; 525 } 526 if (client->mode >= NBD_MODE_EXTENDED && client->contexts.count) { 527 myflags |= NBD_FLAG_BLOCK_STAT_PAYLOAD; 528 } 529 trace_nbd_negotiate_new_style_size_flags(client->exp->size, myflags); 530 stq_be_p(buf, client->exp->size); 531 stw_be_p(buf + 8, myflags); 532 len = no_zeroes ? 10 : sizeof(buf); 533 ret = nbd_write(client->ioc, buf, len, errp); 534 if (ret < 0) { 535 error_prepend(errp, "write failed: "); 536 return ret; 537 } 538 539 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 540 blk_exp_ref(&client->exp->common); 541 542 return 0; 543 } 544 545 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 546 * The buffer does NOT include the info type prefix. 547 * Return -errno on error, 0 if ready to send more. */ 548 static coroutine_fn int 549 nbd_negotiate_send_info(NBDClient *client, uint16_t info, uint32_t length, 550 void *buf, Error **errp) 551 { 552 int rc; 553 554 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 555 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 556 sizeof(info) + length, errp); 557 if (rc < 0) { 558 return rc; 559 } 560 info = cpu_to_be16(info); 561 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 562 return -EIO; 563 } 564 if (nbd_write(client->ioc, buf, length, errp) < 0) { 565 return -EIO; 566 } 567 return 0; 568 } 569 570 /* nbd_reject_length: Handle any unexpected payload. 571 * @fatal requests that we quit talking to the client, even if we are able 572 * to successfully send an error reply. 573 * Return: 574 * -errno transmission error occurred or @fatal was requested, errp is set 575 * 0 error message successfully sent to client, errp is not set 576 */ 577 static coroutine_fn int 578 nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 579 { 580 int ret; 581 582 assert(client->optlen); 583 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length", 584 nbd_opt_lookup(client->opt)); 585 if (fatal && !ret) { 586 error_setg(errp, "option '%s' has unexpected length", 587 nbd_opt_lookup(client->opt)); 588 return -EINVAL; 589 } 590 return ret; 591 } 592 593 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 594 * Return -errno on error, 0 if ready for next option, and 1 to move 595 * into transmission phase. */ 596 static coroutine_fn int 597 nbd_negotiate_handle_info(NBDClient *client, Error **errp) 598 { 599 int rc; 600 g_autofree char *name = NULL; 601 NBDExport *exp; 602 uint16_t requests; 603 uint16_t request; 604 uint32_t namelen = 0; 605 bool sendname = false; 606 bool blocksize = false; 607 uint32_t sizes[3]; 608 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 609 uint32_t check_align = 0; 610 uint16_t myflags; 611 612 /* Client sends: 613 4 bytes: L, name length (can be 0) 614 L bytes: export name 615 2 bytes: N, number of requests (can be 0) 616 N * 2 bytes: N requests 617 */ 618 rc = nbd_opt_read_name(client, &name, &namelen, errp); 619 if (rc <= 0) { 620 return rc; 621 } 622 trace_nbd_negotiate_handle_export_name_request(name); 623 624 rc = nbd_opt_read(client, &requests, sizeof(requests), false, errp); 625 if (rc <= 0) { 626 return rc; 627 } 628 requests = be16_to_cpu(requests); 629 trace_nbd_negotiate_handle_info_requests(requests); 630 while (requests--) { 631 rc = nbd_opt_read(client, &request, sizeof(request), false, errp); 632 if (rc <= 0) { 633 return rc; 634 } 635 request = be16_to_cpu(request); 636 trace_nbd_negotiate_handle_info_request(request, 637 nbd_info_lookup(request)); 638 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 639 * everything else is either a request we don't know or 640 * something we send regardless of request */ 641 switch (request) { 642 case NBD_INFO_NAME: 643 sendname = true; 644 break; 645 case NBD_INFO_BLOCK_SIZE: 646 blocksize = true; 647 break; 648 } 649 } 650 if (client->optlen) { 651 return nbd_reject_length(client, false, errp); 652 } 653 654 exp = nbd_export_find(name); 655 if (!exp) { 656 g_autofree char *sane_name = nbd_sanitize_name(name); 657 658 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 659 errp, "export '%s' not present", 660 sane_name); 661 } 662 if (client->opt == NBD_OPT_GO) { 663 nbd_check_meta_export(client, exp); 664 } 665 666 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 667 if (sendname) { 668 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 669 errp); 670 if (rc < 0) { 671 return rc; 672 } 673 } 674 675 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 676 * client request */ 677 if (exp->description) { 678 size_t len = strlen(exp->description); 679 680 assert(len <= NBD_MAX_STRING_SIZE); 681 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 682 len, exp->description, errp); 683 if (rc < 0) { 684 return rc; 685 } 686 } 687 688 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 689 * according to whether the client requested it, and according to 690 * whether this is OPT_INFO or OPT_GO. */ 691 /* minimum - 1 for back-compat, or actual if client will obey it. */ 692 if (client->opt == NBD_OPT_INFO || blocksize) { 693 check_align = sizes[0] = blk_get_request_alignment(exp->common.blk); 694 } else { 695 sizes[0] = 1; 696 } 697 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE); 698 /* preferred - Hard-code to 4096 for now. 699 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 700 sizes[1] = MAX(4096, sizes[0]); 701 /* maximum - At most 32M, but smaller as appropriate. */ 702 sizes[2] = MIN(blk_get_max_transfer(exp->common.blk), NBD_MAX_BUFFER_SIZE); 703 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 704 sizes[0] = cpu_to_be32(sizes[0]); 705 sizes[1] = cpu_to_be32(sizes[1]); 706 sizes[2] = cpu_to_be32(sizes[2]); 707 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 708 sizeof(sizes), sizes, errp); 709 if (rc < 0) { 710 return rc; 711 } 712 713 /* Send NBD_INFO_EXPORT always */ 714 myflags = exp->nbdflags; 715 if (client->mode >= NBD_MODE_STRUCTURED) { 716 myflags |= NBD_FLAG_SEND_DF; 717 } 718 if (client->mode >= NBD_MODE_EXTENDED && 719 (client->contexts.count || client->opt == NBD_OPT_INFO)) { 720 myflags |= NBD_FLAG_BLOCK_STAT_PAYLOAD; 721 } 722 trace_nbd_negotiate_new_style_size_flags(exp->size, myflags); 723 stq_be_p(buf, exp->size); 724 stw_be_p(buf + 8, myflags); 725 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 726 sizeof(buf), buf, errp); 727 if (rc < 0) { 728 return rc; 729 } 730 731 /* 732 * If the client is just asking for NBD_OPT_INFO, but forgot to 733 * request block sizes in a situation that would impact 734 * performance, then return an error. But for NBD_OPT_GO, we 735 * tolerate all clients, regardless of alignments. 736 */ 737 if (client->opt == NBD_OPT_INFO && !blocksize && 738 blk_get_request_alignment(exp->common.blk) > 1) { 739 return nbd_negotiate_send_rep_err(client, 740 NBD_REP_ERR_BLOCK_SIZE_REQD, 741 errp, 742 "request NBD_INFO_BLOCK_SIZE to " 743 "use this export"); 744 } 745 746 /* Final reply */ 747 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 748 if (rc < 0) { 749 return rc; 750 } 751 752 if (client->opt == NBD_OPT_GO) { 753 client->exp = exp; 754 client->check_align = check_align; 755 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 756 blk_exp_ref(&client->exp->common); 757 rc = 1; 758 } 759 return rc; 760 } 761 762 /* Callback to learn when QIO TLS upgrade is complete */ 763 struct NBDTLSServerHandshakeData { 764 bool complete; 765 Error *error; 766 Coroutine *co; 767 }; 768 769 static void 770 nbd_server_tls_handshake(QIOTask *task, void *opaque) 771 { 772 struct NBDTLSServerHandshakeData *data = opaque; 773 774 qio_task_propagate_error(task, &data->error); 775 data->complete = true; 776 if (!qemu_coroutine_entered(data->co)) { 777 aio_co_wake(data->co); 778 } 779 } 780 781 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 782 * new channel for all further (now-encrypted) communication. */ 783 static coroutine_fn QIOChannel * 784 nbd_negotiate_handle_starttls(NBDClient *client, Error **errp) 785 { 786 QIOChannel *ioc; 787 QIOChannelTLS *tioc; 788 struct NBDTLSServerHandshakeData data = { 0 }; 789 790 assert(client->opt == NBD_OPT_STARTTLS); 791 792 trace_nbd_negotiate_handle_starttls(); 793 ioc = client->ioc; 794 795 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 796 return NULL; 797 } 798 799 tioc = qio_channel_tls_new_server(ioc, 800 client->tlscreds, 801 client->tlsauthz, 802 errp); 803 if (!tioc) { 804 return NULL; 805 } 806 807 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 808 trace_nbd_negotiate_handle_starttls_handshake(); 809 data.co = qemu_coroutine_self(); 810 qio_channel_tls_handshake(tioc, 811 nbd_server_tls_handshake, 812 &data, 813 NULL, 814 NULL); 815 816 if (!data.complete) { 817 qemu_coroutine_yield(); 818 assert(data.complete); 819 } 820 821 if (data.error) { 822 object_unref(OBJECT(tioc)); 823 error_propagate(errp, data.error); 824 return NULL; 825 } 826 827 return QIO_CHANNEL(tioc); 828 } 829 830 /* nbd_negotiate_send_meta_context 831 * 832 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT 833 * 834 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead. 835 */ 836 static coroutine_fn int 837 nbd_negotiate_send_meta_context(NBDClient *client, const char *context, 838 uint32_t context_id, Error **errp) 839 { 840 NBDOptionReplyMetaContext opt; 841 struct iovec iov[] = { 842 {.iov_base = &opt, .iov_len = sizeof(opt)}, 843 {.iov_base = (void *)context, .iov_len = strlen(context)} 844 }; 845 846 assert(iov[1].iov_len <= NBD_MAX_STRING_SIZE); 847 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 848 context_id = 0; 849 } 850 851 trace_nbd_negotiate_meta_query_reply(context, context_id); 852 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT, 853 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len); 854 stl_be_p(&opt.context_id, context_id); 855 856 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; 857 } 858 859 /* 860 * Return true if @query matches @pattern, or if @query is empty when 861 * the @client is performing _LIST_. 862 */ 863 static coroutine_fn bool 864 nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, 865 const char *query) 866 { 867 if (!*query) { 868 trace_nbd_negotiate_meta_query_parse("empty"); 869 return client->opt == NBD_OPT_LIST_META_CONTEXT; 870 } 871 if (strcmp(query, pattern) == 0) { 872 trace_nbd_negotiate_meta_query_parse(pattern); 873 return true; 874 } 875 trace_nbd_negotiate_meta_query_skip("pattern not matched"); 876 return false; 877 } 878 879 /* 880 * Return true and adjust @str in place if it begins with @prefix. 881 */ 882 static coroutine_fn bool 883 nbd_strshift(const char **str, const char *prefix) 884 { 885 size_t len = strlen(prefix); 886 887 if (strncmp(*str, prefix, len) == 0) { 888 *str += len; 889 return true; 890 } 891 return false; 892 } 893 894 /* nbd_meta_base_query 895 * 896 * Handle queries to 'base' namespace. For now, only the base:allocation 897 * context is available. Return true if @query has been handled. 898 */ 899 static coroutine_fn bool 900 nbd_meta_base_query(NBDClient *client, NBDMetaContexts *meta, 901 const char *query) 902 { 903 if (!nbd_strshift(&query, "base:")) { 904 return false; 905 } 906 trace_nbd_negotiate_meta_query_parse("base:"); 907 908 if (nbd_meta_empty_or_pattern(client, "allocation", query)) { 909 meta->base_allocation = true; 910 } 911 return true; 912 } 913 914 /* nbd_meta_qemu_query 915 * 916 * Handle queries to 'qemu' namespace. For now, only the qemu:dirty-bitmap: 917 * and qemu:allocation-depth contexts are available. Return true if @query 918 * has been handled. 919 */ 920 static coroutine_fn bool 921 nbd_meta_qemu_query(NBDClient *client, NBDMetaContexts *meta, 922 const char *query) 923 { 924 size_t i; 925 926 if (!nbd_strshift(&query, "qemu:")) { 927 return false; 928 } 929 trace_nbd_negotiate_meta_query_parse("qemu:"); 930 931 if (!*query) { 932 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 933 meta->allocation_depth = meta->exp->allocation_depth; 934 if (meta->exp->nr_export_bitmaps) { 935 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 936 } 937 } 938 trace_nbd_negotiate_meta_query_parse("empty"); 939 return true; 940 } 941 942 if (strcmp(query, "allocation-depth") == 0) { 943 trace_nbd_negotiate_meta_query_parse("allocation-depth"); 944 meta->allocation_depth = meta->exp->allocation_depth; 945 return true; 946 } 947 948 if (nbd_strshift(&query, "dirty-bitmap:")) { 949 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); 950 if (!*query) { 951 if (client->opt == NBD_OPT_LIST_META_CONTEXT && 952 meta->exp->nr_export_bitmaps) { 953 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 954 } 955 trace_nbd_negotiate_meta_query_parse("empty"); 956 return true; 957 } 958 959 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) { 960 const char *bm_name; 961 962 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]); 963 if (strcmp(bm_name, query) == 0) { 964 meta->bitmaps[i] = true; 965 trace_nbd_negotiate_meta_query_parse(query); 966 return true; 967 } 968 } 969 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap match"); 970 return true; 971 } 972 973 trace_nbd_negotiate_meta_query_skip("unknown qemu context"); 974 return true; 975 } 976 977 /* nbd_negotiate_meta_query 978 * 979 * Parse namespace name and call corresponding function to parse body of the 980 * query. 981 * 982 * The only supported namespaces are 'base' and 'qemu'. 983 * 984 * Return -errno on I/O error, 0 if option was completely handled by 985 * sending a reply about inconsistent lengths, or 1 on success. */ 986 static coroutine_fn int 987 nbd_negotiate_meta_query(NBDClient *client, 988 NBDMetaContexts *meta, Error **errp) 989 { 990 int ret; 991 g_autofree char *query = NULL; 992 uint32_t len; 993 994 ret = nbd_opt_read(client, &len, sizeof(len), false, errp); 995 if (ret <= 0) { 996 return ret; 997 } 998 len = cpu_to_be32(len); 999 1000 if (len > NBD_MAX_STRING_SIZE) { 1001 trace_nbd_negotiate_meta_query_skip("length too long"); 1002 return nbd_opt_skip(client, len, errp); 1003 } 1004 1005 query = g_malloc(len + 1); 1006 ret = nbd_opt_read(client, query, len, true, errp); 1007 if (ret <= 0) { 1008 return ret; 1009 } 1010 query[len] = '\0'; 1011 1012 if (nbd_meta_base_query(client, meta, query)) { 1013 return 1; 1014 } 1015 if (nbd_meta_qemu_query(client, meta, query)) { 1016 return 1; 1017 } 1018 1019 trace_nbd_negotiate_meta_query_skip("unknown namespace"); 1020 return 1; 1021 } 1022 1023 /* nbd_negotiate_meta_queries 1024 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT 1025 * 1026 * Return -errno on I/O error, or 0 if option was completely handled. */ 1027 static coroutine_fn int 1028 nbd_negotiate_meta_queries(NBDClient *client, Error **errp) 1029 { 1030 int ret; 1031 g_autofree char *export_name = NULL; 1032 /* Mark unused to work around https://bugs.llvm.org/show_bug.cgi?id=3888 */ 1033 g_autofree G_GNUC_UNUSED bool *bitmaps = NULL; 1034 NBDMetaContexts local_meta = {0}; 1035 NBDMetaContexts *meta; 1036 uint32_t nb_queries; 1037 size_t i; 1038 size_t count = 0; 1039 1040 if (client->opt == NBD_OPT_SET_META_CONTEXT && 1041 client->mode < NBD_MODE_STRUCTURED) { 1042 return nbd_opt_invalid(client, errp, 1043 "request option '%s' when structured reply " 1044 "is not negotiated", 1045 nbd_opt_lookup(client->opt)); 1046 } 1047 1048 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 1049 /* Only change the caller's meta on SET. */ 1050 meta = &local_meta; 1051 } else { 1052 meta = &client->contexts; 1053 } 1054 1055 g_free(meta->bitmaps); 1056 memset(meta, 0, sizeof(*meta)); 1057 1058 ret = nbd_opt_read_name(client, &export_name, NULL, errp); 1059 if (ret <= 0) { 1060 return ret; 1061 } 1062 1063 meta->exp = nbd_export_find(export_name); 1064 if (meta->exp == NULL) { 1065 g_autofree char *sane_name = nbd_sanitize_name(export_name); 1066 1067 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, 1068 "export '%s' not present", sane_name); 1069 } 1070 meta->bitmaps = g_new0(bool, meta->exp->nr_export_bitmaps); 1071 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 1072 bitmaps = meta->bitmaps; 1073 } 1074 1075 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), false, errp); 1076 if (ret <= 0) { 1077 return ret; 1078 } 1079 nb_queries = cpu_to_be32(nb_queries); 1080 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), 1081 export_name, nb_queries); 1082 1083 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { 1084 /* enable all known contexts */ 1085 meta->base_allocation = true; 1086 meta->allocation_depth = meta->exp->allocation_depth; 1087 if (meta->exp->nr_export_bitmaps) { 1088 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 1089 } 1090 } else { 1091 for (i = 0; i < nb_queries; ++i) { 1092 ret = nbd_negotiate_meta_query(client, meta, errp); 1093 if (ret <= 0) { 1094 return ret; 1095 } 1096 } 1097 } 1098 1099 if (meta->base_allocation) { 1100 ret = nbd_negotiate_send_meta_context(client, "base:allocation", 1101 NBD_META_ID_BASE_ALLOCATION, 1102 errp); 1103 if (ret < 0) { 1104 return ret; 1105 } 1106 count++; 1107 } 1108 1109 if (meta->allocation_depth) { 1110 ret = nbd_negotiate_send_meta_context(client, "qemu:allocation-depth", 1111 NBD_META_ID_ALLOCATION_DEPTH, 1112 errp); 1113 if (ret < 0) { 1114 return ret; 1115 } 1116 count++; 1117 } 1118 1119 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) { 1120 const char *bm_name; 1121 g_autofree char *context = NULL; 1122 1123 if (!meta->bitmaps[i]) { 1124 continue; 1125 } 1126 1127 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]); 1128 context = g_strdup_printf("qemu:dirty-bitmap:%s", bm_name); 1129 1130 ret = nbd_negotiate_send_meta_context(client, context, 1131 NBD_META_ID_DIRTY_BITMAP + i, 1132 errp); 1133 if (ret < 0) { 1134 return ret; 1135 } 1136 count++; 1137 } 1138 1139 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1140 if (ret == 0) { 1141 meta->count = count; 1142 } 1143 1144 return ret; 1145 } 1146 1147 /* nbd_negotiate_options 1148 * Process all NBD_OPT_* client option commands, during fixed newstyle 1149 * negotiation. 1150 * Return: 1151 * -errno on error, errp is set 1152 * 0 on successful negotiation, errp is not set 1153 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1154 * errp is not set 1155 */ 1156 static coroutine_fn int 1157 nbd_negotiate_options(NBDClient *client, Error **errp) 1158 { 1159 uint32_t flags; 1160 bool fixedNewstyle = false; 1161 bool no_zeroes = false; 1162 1163 /* Client sends: 1164 [ 0 .. 3] client flags 1165 1166 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 1167 [ 0 .. 7] NBD_OPTS_MAGIC 1168 [ 8 .. 11] NBD option 1169 [12 .. 15] Data length 1170 ... Rest of request 1171 1172 [ 0 .. 7] NBD_OPTS_MAGIC 1173 [ 8 .. 11] Second NBD option 1174 [12 .. 15] Data length 1175 ... Rest of request 1176 */ 1177 1178 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) { 1179 return -EIO; 1180 } 1181 client->mode = NBD_MODE_EXPORT_NAME; 1182 trace_nbd_negotiate_options_flags(flags); 1183 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1184 fixedNewstyle = true; 1185 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1186 client->mode = NBD_MODE_SIMPLE; 1187 } 1188 if (flags & NBD_FLAG_C_NO_ZEROES) { 1189 no_zeroes = true; 1190 flags &= ~NBD_FLAG_C_NO_ZEROES; 1191 } 1192 if (flags != 0) { 1193 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1194 return -EINVAL; 1195 } 1196 1197 while (1) { 1198 int ret; 1199 uint32_t option, length; 1200 uint64_t magic; 1201 1202 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) { 1203 return -EINVAL; 1204 } 1205 trace_nbd_negotiate_options_check_magic(magic); 1206 if (magic != NBD_OPTS_MAGIC) { 1207 error_setg(errp, "Bad magic received"); 1208 return -EINVAL; 1209 } 1210 1211 if (nbd_read32(client->ioc, &option, "option", errp) < 0) { 1212 return -EINVAL; 1213 } 1214 client->opt = option; 1215 1216 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) { 1217 return -EINVAL; 1218 } 1219 assert(!client->optlen); 1220 client->optlen = length; 1221 1222 if (length > NBD_MAX_BUFFER_SIZE) { 1223 error_setg(errp, "len (%" PRIu32 ") is larger than max len (%u)", 1224 length, NBD_MAX_BUFFER_SIZE); 1225 return -EINVAL; 1226 } 1227 1228 trace_nbd_negotiate_options_check_option(option, 1229 nbd_opt_lookup(option)); 1230 if (client->tlscreds && 1231 client->ioc == (QIOChannel *)client->sioc) { 1232 QIOChannel *tioc; 1233 if (!fixedNewstyle) { 1234 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1235 return -EINVAL; 1236 } 1237 switch (option) { 1238 case NBD_OPT_STARTTLS: 1239 if (length) { 1240 /* Unconditionally drop the connection if the client 1241 * can't start a TLS negotiation correctly */ 1242 return nbd_reject_length(client, true, errp); 1243 } 1244 tioc = nbd_negotiate_handle_starttls(client, errp); 1245 if (!tioc) { 1246 return -EIO; 1247 } 1248 ret = 0; 1249 object_unref(OBJECT(client->ioc)); 1250 client->ioc = tioc; 1251 break; 1252 1253 case NBD_OPT_EXPORT_NAME: 1254 /* No way to return an error to client, so drop connection */ 1255 error_setg(errp, "Option 0x%x not permitted before TLS", 1256 option); 1257 return -EINVAL; 1258 1259 default: 1260 /* Let the client keep trying, unless they asked to 1261 * quit. Always try to give an error back to the 1262 * client; but when replying to OPT_ABORT, be aware 1263 * that the client may hang up before receiving the 1264 * error, in which case we are fine ignoring the 1265 * resulting EPIPE. */ 1266 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, 1267 option == NBD_OPT_ABORT ? NULL : errp, 1268 "Option 0x%" PRIx32 1269 " not permitted before TLS", option); 1270 if (option == NBD_OPT_ABORT) { 1271 return 1; 1272 } 1273 break; 1274 } 1275 } else if (fixedNewstyle) { 1276 switch (option) { 1277 case NBD_OPT_LIST: 1278 if (length) { 1279 ret = nbd_reject_length(client, false, errp); 1280 } else { 1281 ret = nbd_negotiate_handle_list(client, errp); 1282 } 1283 break; 1284 1285 case NBD_OPT_ABORT: 1286 /* NBD spec says we must try to reply before 1287 * disconnecting, but that we must also tolerate 1288 * guests that don't wait for our reply. */ 1289 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1290 return 1; 1291 1292 case NBD_OPT_EXPORT_NAME: 1293 return nbd_negotiate_handle_export_name(client, no_zeroes, 1294 errp); 1295 1296 case NBD_OPT_INFO: 1297 case NBD_OPT_GO: 1298 ret = nbd_negotiate_handle_info(client, errp); 1299 if (ret == 1) { 1300 assert(option == NBD_OPT_GO); 1301 return 0; 1302 } 1303 break; 1304 1305 case NBD_OPT_STARTTLS: 1306 if (length) { 1307 ret = nbd_reject_length(client, false, errp); 1308 } else if (client->tlscreds) { 1309 ret = nbd_negotiate_send_rep_err(client, 1310 NBD_REP_ERR_INVALID, errp, 1311 "TLS already enabled"); 1312 } else { 1313 ret = nbd_negotiate_send_rep_err(client, 1314 NBD_REP_ERR_POLICY, errp, 1315 "TLS not configured"); 1316 } 1317 break; 1318 1319 case NBD_OPT_STRUCTURED_REPLY: 1320 if (length) { 1321 ret = nbd_reject_length(client, false, errp); 1322 } else if (client->mode >= NBD_MODE_EXTENDED) { 1323 ret = nbd_negotiate_send_rep_err( 1324 client, NBD_REP_ERR_EXT_HEADER_REQD, errp, 1325 "extended headers already negotiated"); 1326 } else if (client->mode >= NBD_MODE_STRUCTURED) { 1327 ret = nbd_negotiate_send_rep_err( 1328 client, NBD_REP_ERR_INVALID, errp, 1329 "structured reply already negotiated"); 1330 } else { 1331 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1332 client->mode = NBD_MODE_STRUCTURED; 1333 } 1334 break; 1335 1336 case NBD_OPT_LIST_META_CONTEXT: 1337 case NBD_OPT_SET_META_CONTEXT: 1338 ret = nbd_negotiate_meta_queries(client, errp); 1339 break; 1340 1341 case NBD_OPT_EXTENDED_HEADERS: 1342 if (length) { 1343 ret = nbd_reject_length(client, false, errp); 1344 } else if (client->mode >= NBD_MODE_EXTENDED) { 1345 ret = nbd_negotiate_send_rep_err( 1346 client, NBD_REP_ERR_INVALID, errp, 1347 "extended headers already negotiated"); 1348 } else { 1349 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1350 client->mode = NBD_MODE_EXTENDED; 1351 } 1352 break; 1353 1354 default: 1355 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1356 "Unsupported option %" PRIu32 " (%s)", 1357 option, nbd_opt_lookup(option)); 1358 break; 1359 } 1360 } else { 1361 /* 1362 * If broken new-style we should drop the connection 1363 * for anything except NBD_OPT_EXPORT_NAME 1364 */ 1365 switch (option) { 1366 case NBD_OPT_EXPORT_NAME: 1367 return nbd_negotiate_handle_export_name(client, no_zeroes, 1368 errp); 1369 1370 default: 1371 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1372 option, nbd_opt_lookup(option)); 1373 return -EINVAL; 1374 } 1375 } 1376 if (ret < 0) { 1377 return ret; 1378 } 1379 } 1380 } 1381 1382 /* nbd_negotiate 1383 * Return: 1384 * -errno on error, errp is set 1385 * 0 on successful negotiation, errp is not set 1386 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1387 * errp is not set 1388 */ 1389 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1390 { 1391 ERRP_GUARD(); 1392 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1393 int ret; 1394 1395 /* Old style negotiation header, no room for options 1396 [ 0 .. 7] passwd ("NBDMAGIC") 1397 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1398 [16 .. 23] size 1399 [24 .. 27] export flags (zero-extended) 1400 [28 .. 151] reserved (0) 1401 1402 New style negotiation header, client can send options 1403 [ 0 .. 7] passwd ("NBDMAGIC") 1404 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1405 [16 .. 17] server flags (0) 1406 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1407 */ 1408 1409 qio_channel_set_blocking(client->ioc, false, NULL); 1410 qio_channel_set_follow_coroutine_ctx(client->ioc, true); 1411 1412 trace_nbd_negotiate_begin(); 1413 memcpy(buf, "NBDMAGIC", 8); 1414 1415 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1416 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1417 1418 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 1419 error_prepend(errp, "write failed: "); 1420 return -EINVAL; 1421 } 1422 ret = nbd_negotiate_options(client, errp); 1423 if (ret != 0) { 1424 if (ret < 0) { 1425 error_prepend(errp, "option negotiation failed: "); 1426 } 1427 return ret; 1428 } 1429 1430 assert(!client->optlen); 1431 trace_nbd_negotiate_success(); 1432 1433 return 0; 1434 } 1435 1436 /* nbd_read_eof 1437 * Tries to read @size bytes from @ioc. This is a local implementation of 1438 * qio_channel_readv_all_eof. We have it here because we need it to be 1439 * interruptible and to know when the coroutine is yielding. 1440 * Returns 1 on success 1441 * 0 on eof, when no data was read (errp is not set) 1442 * negative errno on failure (errp is set) 1443 */ 1444 static inline int coroutine_fn 1445 nbd_read_eof(NBDClient *client, void *buffer, size_t size, Error **errp) 1446 { 1447 bool partial = false; 1448 1449 assert(size); 1450 while (size > 0) { 1451 struct iovec iov = { .iov_base = buffer, .iov_len = size }; 1452 ssize_t len; 1453 1454 len = qio_channel_readv(client->ioc, &iov, 1, errp); 1455 if (len == QIO_CHANNEL_ERR_BLOCK) { 1456 WITH_QEMU_LOCK_GUARD(&client->lock) { 1457 client->read_yielding = true; 1458 1459 /* Prompt main loop thread to re-run nbd_drained_poll() */ 1460 aio_wait_kick(); 1461 } 1462 qio_channel_yield(client->ioc, G_IO_IN); 1463 WITH_QEMU_LOCK_GUARD(&client->lock) { 1464 client->read_yielding = false; 1465 if (client->quiescing) { 1466 return -EAGAIN; 1467 } 1468 } 1469 continue; 1470 } else if (len < 0) { 1471 return -EIO; 1472 } else if (len == 0) { 1473 if (partial) { 1474 error_setg(errp, 1475 "Unexpected end-of-file before all bytes were read"); 1476 return -EIO; 1477 } else { 1478 return 0; 1479 } 1480 } 1481 1482 partial = true; 1483 size -= len; 1484 buffer = (uint8_t *) buffer + len; 1485 } 1486 return 1; 1487 } 1488 1489 static int coroutine_fn nbd_receive_request(NBDClient *client, NBDRequest *request, 1490 Error **errp) 1491 { 1492 uint8_t buf[NBD_EXTENDED_REQUEST_SIZE]; 1493 uint32_t magic, expect; 1494 int ret; 1495 size_t size = client->mode >= NBD_MODE_EXTENDED ? 1496 NBD_EXTENDED_REQUEST_SIZE : NBD_REQUEST_SIZE; 1497 1498 ret = nbd_read_eof(client, buf, size, errp); 1499 if (ret < 0) { 1500 return ret; 1501 } 1502 if (ret == 0) { 1503 return -EIO; 1504 } 1505 1506 /* 1507 * Compact request 1508 * [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1509 * [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1510 * [ 6 .. 7] type (NBD_CMD_READ, ...) 1511 * [ 8 .. 15] cookie 1512 * [16 .. 23] from 1513 * [24 .. 27] len 1514 * Extended request 1515 * [ 0 .. 3] magic (NBD_EXTENDED_REQUEST_MAGIC) 1516 * [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, NBD_CMD_FLAG_PAYLOAD_LEN, ...) 1517 * [ 6 .. 7] type (NBD_CMD_READ, ...) 1518 * [ 8 .. 15] cookie 1519 * [16 .. 23] from 1520 * [24 .. 31] len 1521 */ 1522 1523 magic = ldl_be_p(buf); 1524 request->flags = lduw_be_p(buf + 4); 1525 request->type = lduw_be_p(buf + 6); 1526 request->cookie = ldq_be_p(buf + 8); 1527 request->from = ldq_be_p(buf + 16); 1528 if (client->mode >= NBD_MODE_EXTENDED) { 1529 request->len = ldq_be_p(buf + 24); 1530 expect = NBD_EXTENDED_REQUEST_MAGIC; 1531 } else { 1532 request->len = (uint32_t)ldl_be_p(buf + 24); /* widen 32 to 64 bits */ 1533 expect = NBD_REQUEST_MAGIC; 1534 } 1535 1536 trace_nbd_receive_request(magic, request->flags, request->type, 1537 request->from, request->len); 1538 1539 if (magic != expect) { 1540 error_setg(errp, "invalid magic (got 0x%" PRIx32 ", expected 0x%" 1541 PRIx32 ")", magic, expect); 1542 return -EINVAL; 1543 } 1544 return 0; 1545 } 1546 1547 #define MAX_NBD_REQUESTS 16 1548 1549 /* Runs in export AioContext and main loop thread */ 1550 void nbd_client_get(NBDClient *client) 1551 { 1552 qatomic_inc(&client->refcount); 1553 } 1554 1555 void nbd_client_put(NBDClient *client) 1556 { 1557 assert(qemu_in_main_thread()); 1558 1559 if (qatomic_fetch_dec(&client->refcount) == 1) { 1560 /* The last reference should be dropped by client->close, 1561 * which is called by client_close. 1562 */ 1563 assert(client->closing); 1564 1565 object_unref(OBJECT(client->sioc)); 1566 object_unref(OBJECT(client->ioc)); 1567 if (client->tlscreds) { 1568 object_unref(OBJECT(client->tlscreds)); 1569 } 1570 g_free(client->tlsauthz); 1571 if (client->exp) { 1572 QTAILQ_REMOVE(&client->exp->clients, client, next); 1573 blk_exp_unref(&client->exp->common); 1574 } 1575 g_free(client->contexts.bitmaps); 1576 qemu_mutex_destroy(&client->lock); 1577 g_free(client); 1578 } 1579 } 1580 1581 /* 1582 * Tries to release the reference to @client, but only if other references 1583 * remain. This is an optimization for the common case where we want to avoid 1584 * the expense of scheduling nbd_client_put() in the main loop thread. 1585 * 1586 * Returns true upon success or false if the reference was not released because 1587 * it is the last reference. 1588 */ 1589 static bool nbd_client_put_nonzero(NBDClient *client) 1590 { 1591 int old = qatomic_read(&client->refcount); 1592 int expected; 1593 1594 do { 1595 if (old == 1) { 1596 return false; 1597 } 1598 1599 expected = old; 1600 old = qatomic_cmpxchg(&client->refcount, expected, expected - 1); 1601 } while (old != expected); 1602 1603 return true; 1604 } 1605 1606 static void client_close(NBDClient *client, bool negotiated) 1607 { 1608 assert(qemu_in_main_thread()); 1609 1610 WITH_QEMU_LOCK_GUARD(&client->lock) { 1611 if (client->closing) { 1612 return; 1613 } 1614 1615 client->closing = true; 1616 } 1617 1618 /* Force requests to finish. They will drop their own references, 1619 * then we'll close the socket and free the NBDClient. 1620 */ 1621 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1622 NULL); 1623 1624 /* Also tell the client, so that they release their reference. */ 1625 if (client->close_fn) { 1626 client->close_fn(client, negotiated); 1627 } 1628 } 1629 1630 /* Runs in export AioContext with client->lock held */ 1631 static NBDRequestData *nbd_request_get(NBDClient *client) 1632 { 1633 NBDRequestData *req; 1634 1635 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1636 client->nb_requests++; 1637 1638 req = g_new0(NBDRequestData, 1); 1639 req->client = client; 1640 return req; 1641 } 1642 1643 /* Runs in export AioContext with client->lock held */ 1644 static void nbd_request_put(NBDRequestData *req) 1645 { 1646 NBDClient *client = req->client; 1647 1648 if (req->data) { 1649 qemu_vfree(req->data); 1650 } 1651 g_free(req); 1652 1653 client->nb_requests--; 1654 1655 if (client->quiescing && client->nb_requests == 0) { 1656 aio_wait_kick(); 1657 } 1658 1659 nbd_client_receive_next_request(client); 1660 } 1661 1662 static void blk_aio_attached(AioContext *ctx, void *opaque) 1663 { 1664 NBDExport *exp = opaque; 1665 NBDClient *client; 1666 1667 assert(qemu_in_main_thread()); 1668 1669 trace_nbd_blk_aio_attached(exp->name, ctx); 1670 1671 exp->common.ctx = ctx; 1672 1673 QTAILQ_FOREACH(client, &exp->clients, next) { 1674 WITH_QEMU_LOCK_GUARD(&client->lock) { 1675 assert(client->nb_requests == 0); 1676 assert(client->recv_coroutine == NULL); 1677 assert(client->send_coroutine == NULL); 1678 } 1679 } 1680 } 1681 1682 static void blk_aio_detach(void *opaque) 1683 { 1684 NBDExport *exp = opaque; 1685 1686 assert(qemu_in_main_thread()); 1687 1688 trace_nbd_blk_aio_detach(exp->name, exp->common.ctx); 1689 1690 exp->common.ctx = NULL; 1691 } 1692 1693 static void nbd_drained_begin(void *opaque) 1694 { 1695 NBDExport *exp = opaque; 1696 NBDClient *client; 1697 1698 assert(qemu_in_main_thread()); 1699 1700 QTAILQ_FOREACH(client, &exp->clients, next) { 1701 WITH_QEMU_LOCK_GUARD(&client->lock) { 1702 client->quiescing = true; 1703 } 1704 } 1705 } 1706 1707 static void nbd_drained_end(void *opaque) 1708 { 1709 NBDExport *exp = opaque; 1710 NBDClient *client; 1711 1712 assert(qemu_in_main_thread()); 1713 1714 QTAILQ_FOREACH(client, &exp->clients, next) { 1715 WITH_QEMU_LOCK_GUARD(&client->lock) { 1716 client->quiescing = false; 1717 nbd_client_receive_next_request(client); 1718 } 1719 } 1720 } 1721 1722 /* Runs in export AioContext */ 1723 static void nbd_wake_read_bh(void *opaque) 1724 { 1725 NBDClient *client = opaque; 1726 qio_channel_wake_read(client->ioc); 1727 } 1728 1729 static bool nbd_drained_poll(void *opaque) 1730 { 1731 NBDExport *exp = opaque; 1732 NBDClient *client; 1733 1734 assert(qemu_in_main_thread()); 1735 1736 QTAILQ_FOREACH(client, &exp->clients, next) { 1737 WITH_QEMU_LOCK_GUARD(&client->lock) { 1738 if (client->nb_requests != 0) { 1739 /* 1740 * If there's a coroutine waiting for a request on nbd_read_eof() 1741 * enter it here so we don't depend on the client to wake it up. 1742 * 1743 * Schedule a BH in the export AioContext to avoid missing the 1744 * wake up due to the race between qio_channel_wake_read() and 1745 * qio_channel_yield(). 1746 */ 1747 if (client->recv_coroutine != NULL && client->read_yielding) { 1748 aio_bh_schedule_oneshot(nbd_export_aio_context(client->exp), 1749 nbd_wake_read_bh, client); 1750 } 1751 1752 return true; 1753 } 1754 } 1755 } 1756 1757 return false; 1758 } 1759 1760 static void nbd_eject_notifier(Notifier *n, void *data) 1761 { 1762 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1763 1764 assert(qemu_in_main_thread()); 1765 1766 blk_exp_request_shutdown(&exp->common); 1767 } 1768 1769 void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk) 1770 { 1771 NBDExport *nbd_exp = container_of(exp, NBDExport, common); 1772 assert(exp->drv == &blk_exp_nbd); 1773 assert(nbd_exp->eject_notifier_blk == NULL); 1774 1775 blk_ref(blk); 1776 nbd_exp->eject_notifier_blk = blk; 1777 nbd_exp->eject_notifier.notify = nbd_eject_notifier; 1778 blk_add_remove_bs_notifier(blk, &nbd_exp->eject_notifier); 1779 } 1780 1781 static const BlockDevOps nbd_block_ops = { 1782 .drained_begin = nbd_drained_begin, 1783 .drained_end = nbd_drained_end, 1784 .drained_poll = nbd_drained_poll, 1785 }; 1786 1787 static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args, 1788 Error **errp) 1789 { 1790 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1791 BlockExportOptionsNbd *arg = &exp_args->u.nbd; 1792 const char *name = arg->name ?: exp_args->node_name; 1793 BlockBackend *blk = blk_exp->blk; 1794 int64_t size; 1795 uint64_t perm, shared_perm; 1796 bool readonly = !exp_args->writable; 1797 BlockDirtyBitmapOrStrList *bitmaps; 1798 size_t i; 1799 int ret; 1800 1801 GLOBAL_STATE_CODE(); 1802 assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD); 1803 1804 if (!nbd_server_is_running()) { 1805 error_setg(errp, "NBD server not running"); 1806 return -EINVAL; 1807 } 1808 1809 if (strlen(name) > NBD_MAX_STRING_SIZE) { 1810 error_setg(errp, "export name '%s' too long", name); 1811 return -EINVAL; 1812 } 1813 1814 if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) { 1815 error_setg(errp, "description '%s' too long", arg->description); 1816 return -EINVAL; 1817 } 1818 1819 if (nbd_export_find(name)) { 1820 error_setg(errp, "NBD server already has export named '%s'", name); 1821 return -EEXIST; 1822 } 1823 1824 size = blk_getlength(blk); 1825 if (size < 0) { 1826 error_setg_errno(errp, -size, 1827 "Failed to determine the NBD export's length"); 1828 return size; 1829 } 1830 1831 /* Don't allow resize while the NBD server is running, otherwise we don't 1832 * care what happens with the node. */ 1833 blk_get_perm(blk, &perm, &shared_perm); 1834 ret = blk_set_perm(blk, perm, shared_perm & ~BLK_PERM_RESIZE, errp); 1835 if (ret < 0) { 1836 return ret; 1837 } 1838 1839 QTAILQ_INIT(&exp->clients); 1840 exp->name = g_strdup(name); 1841 exp->description = g_strdup(arg->description); 1842 exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH | 1843 NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE); 1844 1845 if (nbd_server_max_connections() != 1) { 1846 exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN; 1847 } 1848 if (readonly) { 1849 exp->nbdflags |= NBD_FLAG_READ_ONLY; 1850 } else { 1851 exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES | 1852 NBD_FLAG_SEND_FAST_ZERO); 1853 } 1854 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); 1855 1856 bdrv_graph_rdlock_main_loop(); 1857 1858 for (bitmaps = arg->bitmaps; bitmaps; bitmaps = bitmaps->next) { 1859 exp->nr_export_bitmaps++; 1860 } 1861 exp->export_bitmaps = g_new0(BdrvDirtyBitmap *, exp->nr_export_bitmaps); 1862 for (i = 0, bitmaps = arg->bitmaps; bitmaps; 1863 i++, bitmaps = bitmaps->next) 1864 { 1865 const char *bitmap; 1866 BlockDriverState *bs = blk_bs(blk); 1867 BdrvDirtyBitmap *bm = NULL; 1868 1869 switch (bitmaps->value->type) { 1870 case QTYPE_QSTRING: 1871 bitmap = bitmaps->value->u.local; 1872 while (bs) { 1873 bm = bdrv_find_dirty_bitmap(bs, bitmap); 1874 if (bm != NULL) { 1875 break; 1876 } 1877 1878 bs = bdrv_filter_or_cow_bs(bs); 1879 } 1880 1881 if (bm == NULL) { 1882 ret = -ENOENT; 1883 error_setg(errp, "Bitmap '%s' is not found", 1884 bitmaps->value->u.local); 1885 goto fail; 1886 } 1887 1888 if (readonly && bdrv_is_writable(bs) && 1889 bdrv_dirty_bitmap_enabled(bm)) { 1890 ret = -EINVAL; 1891 error_setg(errp, "Enabled bitmap '%s' incompatible with " 1892 "readonly export", bitmap); 1893 goto fail; 1894 } 1895 break; 1896 case QTYPE_QDICT: 1897 bitmap = bitmaps->value->u.external.name; 1898 bm = block_dirty_bitmap_lookup(bitmaps->value->u.external.node, 1899 bitmap, NULL, errp); 1900 if (!bm) { 1901 ret = -ENOENT; 1902 goto fail; 1903 } 1904 break; 1905 default: 1906 abort(); 1907 } 1908 1909 assert(bm); 1910 1911 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) { 1912 ret = -EINVAL; 1913 goto fail; 1914 } 1915 1916 exp->export_bitmaps[i] = bm; 1917 assert(strlen(bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE); 1918 } 1919 1920 /* Mark bitmaps busy in a separate loop, to simplify roll-back concerns. */ 1921 for (i = 0; i < exp->nr_export_bitmaps; i++) { 1922 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], true); 1923 } 1924 1925 exp->allocation_depth = arg->allocation_depth; 1926 1927 /* 1928 * We need to inhibit request queuing in the block layer to ensure we can 1929 * be properly quiesced when entering a drained section, as our coroutines 1930 * servicing pending requests might enter blk_pread(). 1931 */ 1932 blk_set_disable_request_queuing(blk, true); 1933 1934 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1935 1936 blk_set_dev_ops(blk, &nbd_block_ops, exp); 1937 1938 QTAILQ_INSERT_TAIL(&exports, exp, next); 1939 1940 bdrv_graph_rdunlock_main_loop(); 1941 1942 return 0; 1943 1944 fail: 1945 bdrv_graph_rdunlock_main_loop(); 1946 g_free(exp->export_bitmaps); 1947 g_free(exp->name); 1948 g_free(exp->description); 1949 return ret; 1950 } 1951 1952 NBDExport *nbd_export_find(const char *name) 1953 { 1954 NBDExport *exp; 1955 QTAILQ_FOREACH(exp, &exports, next) { 1956 if (strcmp(name, exp->name) == 0) { 1957 return exp; 1958 } 1959 } 1960 1961 return NULL; 1962 } 1963 1964 AioContext * 1965 nbd_export_aio_context(NBDExport *exp) 1966 { 1967 return exp->common.ctx; 1968 } 1969 1970 static void nbd_export_request_shutdown(BlockExport *blk_exp) 1971 { 1972 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1973 NBDClient *client, *next; 1974 1975 blk_exp_ref(&exp->common); 1976 /* 1977 * TODO: Should we expand QMP BlockExportRemoveMode enum to allow a 1978 * close mode that stops advertising the export to new clients but 1979 * still permits existing clients to run to completion? Because of 1980 * that possibility, nbd_export_close() can be called more than 1981 * once on an export. 1982 */ 1983 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1984 client_close(client, true); 1985 } 1986 if (exp->name) { 1987 g_free(exp->name); 1988 exp->name = NULL; 1989 QTAILQ_REMOVE(&exports, exp, next); 1990 } 1991 blk_exp_unref(&exp->common); 1992 } 1993 1994 static void nbd_export_delete(BlockExport *blk_exp) 1995 { 1996 size_t i; 1997 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1998 1999 assert(exp->name == NULL); 2000 assert(QTAILQ_EMPTY(&exp->clients)); 2001 2002 g_free(exp->description); 2003 exp->description = NULL; 2004 2005 if (exp->eject_notifier_blk) { 2006 notifier_remove(&exp->eject_notifier); 2007 blk_unref(exp->eject_notifier_blk); 2008 } 2009 blk_remove_aio_context_notifier(exp->common.blk, blk_aio_attached, 2010 blk_aio_detach, exp); 2011 blk_set_disable_request_queuing(exp->common.blk, false); 2012 2013 for (i = 0; i < exp->nr_export_bitmaps; i++) { 2014 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], false); 2015 } 2016 } 2017 2018 const BlockExportDriver blk_exp_nbd = { 2019 .type = BLOCK_EXPORT_TYPE_NBD, 2020 .instance_size = sizeof(NBDExport), 2021 .create = nbd_export_create, 2022 .delete = nbd_export_delete, 2023 .request_shutdown = nbd_export_request_shutdown, 2024 }; 2025 2026 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 2027 unsigned niov, Error **errp) 2028 { 2029 int ret; 2030 2031 g_assert(qemu_in_coroutine()); 2032 qemu_co_mutex_lock(&client->send_lock); 2033 client->send_coroutine = qemu_coroutine_self(); 2034 2035 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 2036 2037 client->send_coroutine = NULL; 2038 qemu_co_mutex_unlock(&client->send_lock); 2039 2040 return ret; 2041 } 2042 2043 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 2044 uint64_t cookie) 2045 { 2046 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 2047 stl_be_p(&reply->error, error); 2048 stq_be_p(&reply->cookie, cookie); 2049 } 2050 2051 static int coroutine_fn nbd_co_send_simple_reply(NBDClient *client, 2052 NBDRequest *request, 2053 uint32_t error, 2054 void *data, 2055 uint64_t len, 2056 Error **errp) 2057 { 2058 NBDSimpleReply reply; 2059 int nbd_err = system_errno_to_nbd_errno(error); 2060 struct iovec iov[] = { 2061 {.iov_base = &reply, .iov_len = sizeof(reply)}, 2062 {.iov_base = data, .iov_len = len} 2063 }; 2064 2065 assert(!len || !nbd_err); 2066 assert(len <= NBD_MAX_BUFFER_SIZE); 2067 assert(client->mode < NBD_MODE_STRUCTURED || 2068 (client->mode == NBD_MODE_STRUCTURED && 2069 request->type != NBD_CMD_READ)); 2070 trace_nbd_co_send_simple_reply(request->cookie, nbd_err, 2071 nbd_err_lookup(nbd_err), len); 2072 set_be_simple_reply(&reply, nbd_err, request->cookie); 2073 2074 return nbd_co_send_iov(client, iov, 2, errp); 2075 } 2076 2077 /* 2078 * Prepare the header of a reply chunk for network transmission. 2079 * 2080 * On input, @iov is partially initialized: iov[0].iov_base must point 2081 * to an uninitialized NBDReply, while the remaining @niov elements 2082 * (if any) must be ready for transmission. This function then 2083 * populates iov[0] for transmission. 2084 */ 2085 static inline void set_be_chunk(NBDClient *client, struct iovec *iov, 2086 size_t niov, uint16_t flags, uint16_t type, 2087 NBDRequest *request) 2088 { 2089 size_t i, length = 0; 2090 2091 for (i = 1; i < niov; i++) { 2092 length += iov[i].iov_len; 2093 } 2094 assert(length <= NBD_MAX_BUFFER_SIZE + sizeof(NBDStructuredReadData)); 2095 2096 if (client->mode >= NBD_MODE_EXTENDED) { 2097 NBDExtendedReplyChunk *chunk = iov->iov_base; 2098 2099 iov[0].iov_len = sizeof(*chunk); 2100 stl_be_p(&chunk->magic, NBD_EXTENDED_REPLY_MAGIC); 2101 stw_be_p(&chunk->flags, flags); 2102 stw_be_p(&chunk->type, type); 2103 stq_be_p(&chunk->cookie, request->cookie); 2104 stq_be_p(&chunk->offset, request->from); 2105 stq_be_p(&chunk->length, length); 2106 } else { 2107 NBDStructuredReplyChunk *chunk = iov->iov_base; 2108 2109 iov[0].iov_len = sizeof(*chunk); 2110 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 2111 stw_be_p(&chunk->flags, flags); 2112 stw_be_p(&chunk->type, type); 2113 stq_be_p(&chunk->cookie, request->cookie); 2114 stl_be_p(&chunk->length, length); 2115 } 2116 } 2117 2118 static int coroutine_fn nbd_co_send_chunk_done(NBDClient *client, 2119 NBDRequest *request, 2120 Error **errp) 2121 { 2122 NBDReply hdr; 2123 struct iovec iov[] = { 2124 {.iov_base = &hdr}, 2125 }; 2126 2127 trace_nbd_co_send_chunk_done(request->cookie); 2128 set_be_chunk(client, iov, 1, NBD_REPLY_FLAG_DONE, 2129 NBD_REPLY_TYPE_NONE, request); 2130 return nbd_co_send_iov(client, iov, 1, errp); 2131 } 2132 2133 static int coroutine_fn nbd_co_send_chunk_read(NBDClient *client, 2134 NBDRequest *request, 2135 uint64_t offset, 2136 void *data, 2137 uint64_t size, 2138 bool final, 2139 Error **errp) 2140 { 2141 NBDReply hdr; 2142 NBDStructuredReadData chunk; 2143 struct iovec iov[] = { 2144 {.iov_base = &hdr}, 2145 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 2146 {.iov_base = data, .iov_len = size} 2147 }; 2148 2149 assert(size && size <= NBD_MAX_BUFFER_SIZE); 2150 trace_nbd_co_send_chunk_read(request->cookie, offset, data, size); 2151 set_be_chunk(client, iov, 3, final ? NBD_REPLY_FLAG_DONE : 0, 2152 NBD_REPLY_TYPE_OFFSET_DATA, request); 2153 stq_be_p(&chunk.offset, offset); 2154 2155 return nbd_co_send_iov(client, iov, 3, errp); 2156 } 2157 2158 static int coroutine_fn nbd_co_send_chunk_error(NBDClient *client, 2159 NBDRequest *request, 2160 uint32_t error, 2161 const char *msg, 2162 Error **errp) 2163 { 2164 NBDReply hdr; 2165 NBDStructuredError chunk; 2166 int nbd_err = system_errno_to_nbd_errno(error); 2167 struct iovec iov[] = { 2168 {.iov_base = &hdr}, 2169 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 2170 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 2171 }; 2172 2173 assert(nbd_err); 2174 trace_nbd_co_send_chunk_error(request->cookie, nbd_err, 2175 nbd_err_lookup(nbd_err), msg ? msg : ""); 2176 set_be_chunk(client, iov, 3, NBD_REPLY_FLAG_DONE, 2177 NBD_REPLY_TYPE_ERROR, request); 2178 stl_be_p(&chunk.error, nbd_err); 2179 stw_be_p(&chunk.message_length, iov[2].iov_len); 2180 2181 return nbd_co_send_iov(client, iov, 3, errp); 2182 } 2183 2184 /* Do a sparse read and send the structured reply to the client. 2185 * Returns -errno if sending fails. blk_co_block_status_above() failure is 2186 * reported to the client, at which point this function succeeds. 2187 */ 2188 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 2189 NBDRequest *request, 2190 uint64_t offset, 2191 uint8_t *data, 2192 uint64_t size, 2193 Error **errp) 2194 { 2195 int ret = 0; 2196 NBDExport *exp = client->exp; 2197 size_t progress = 0; 2198 2199 assert(size <= NBD_MAX_BUFFER_SIZE); 2200 while (progress < size) { 2201 int64_t pnum; 2202 int status = blk_co_block_status_above(exp->common.blk, NULL, 2203 offset + progress, 2204 size - progress, &pnum, NULL, 2205 NULL); 2206 bool final; 2207 2208 if (status < 0) { 2209 char *msg = g_strdup_printf("unable to check for holes: %s", 2210 strerror(-status)); 2211 2212 ret = nbd_co_send_chunk_error(client, request, -status, msg, errp); 2213 g_free(msg); 2214 return ret; 2215 } 2216 assert(pnum && pnum <= size - progress); 2217 final = progress + pnum == size; 2218 if (status & BDRV_BLOCK_ZERO) { 2219 NBDReply hdr; 2220 NBDStructuredReadHole chunk; 2221 struct iovec iov[] = { 2222 {.iov_base = &hdr}, 2223 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 2224 }; 2225 2226 trace_nbd_co_send_chunk_read_hole(request->cookie, 2227 offset + progress, pnum); 2228 set_be_chunk(client, iov, 2, 2229 final ? NBD_REPLY_FLAG_DONE : 0, 2230 NBD_REPLY_TYPE_OFFSET_HOLE, request); 2231 stq_be_p(&chunk.offset, offset + progress); 2232 stl_be_p(&chunk.length, pnum); 2233 ret = nbd_co_send_iov(client, iov, 2, errp); 2234 } else { 2235 ret = blk_co_pread(exp->common.blk, offset + progress, pnum, 2236 data + progress, 0); 2237 if (ret < 0) { 2238 error_setg_errno(errp, -ret, "reading from file failed"); 2239 break; 2240 } 2241 ret = nbd_co_send_chunk_read(client, request, offset + progress, 2242 data + progress, pnum, final, errp); 2243 } 2244 2245 if (ret < 0) { 2246 break; 2247 } 2248 progress += pnum; 2249 } 2250 return ret; 2251 } 2252 2253 typedef struct NBDExtentArray { 2254 NBDExtent64 *extents; 2255 unsigned int nb_alloc; 2256 unsigned int count; 2257 uint64_t total_length; 2258 bool extended; 2259 bool can_add; 2260 bool converted_to_be; 2261 } NBDExtentArray; 2262 2263 static NBDExtentArray *nbd_extent_array_new(unsigned int nb_alloc, 2264 NBDMode mode) 2265 { 2266 NBDExtentArray *ea = g_new0(NBDExtentArray, 1); 2267 2268 assert(mode >= NBD_MODE_STRUCTURED); 2269 ea->nb_alloc = nb_alloc; 2270 ea->extents = g_new(NBDExtent64, nb_alloc); 2271 ea->extended = mode >= NBD_MODE_EXTENDED; 2272 ea->can_add = true; 2273 2274 return ea; 2275 } 2276 2277 static void nbd_extent_array_free(NBDExtentArray *ea) 2278 { 2279 g_free(ea->extents); 2280 g_free(ea); 2281 } 2282 G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray, nbd_extent_array_free) 2283 2284 /* Further modifications of the array after conversion are abandoned */ 2285 static void nbd_extent_array_convert_to_be(NBDExtentArray *ea) 2286 { 2287 int i; 2288 2289 assert(!ea->converted_to_be); 2290 assert(ea->extended); 2291 ea->can_add = false; 2292 ea->converted_to_be = true; 2293 2294 for (i = 0; i < ea->count; i++) { 2295 ea->extents[i].length = cpu_to_be64(ea->extents[i].length); 2296 ea->extents[i].flags = cpu_to_be64(ea->extents[i].flags); 2297 } 2298 } 2299 2300 /* Further modifications of the array after conversion are abandoned */ 2301 static NBDExtent32 *nbd_extent_array_convert_to_narrow(NBDExtentArray *ea) 2302 { 2303 int i; 2304 NBDExtent32 *extents = g_new(NBDExtent32, ea->count); 2305 2306 assert(!ea->converted_to_be); 2307 assert(!ea->extended); 2308 ea->can_add = false; 2309 ea->converted_to_be = true; 2310 2311 for (i = 0; i < ea->count; i++) { 2312 assert((ea->extents[i].length | ea->extents[i].flags) <= UINT32_MAX); 2313 extents[i].length = cpu_to_be32(ea->extents[i].length); 2314 extents[i].flags = cpu_to_be32(ea->extents[i].flags); 2315 } 2316 2317 return extents; 2318 } 2319 2320 /* 2321 * Add extent to NBDExtentArray. If extent can't be added (no available space), 2322 * return -1. 2323 * For safety, when returning -1 for the first time, .can_add is set to false, 2324 * and further calls to nbd_extent_array_add() will crash. 2325 * (this avoids the situation where a caller ignores failure to add one extent, 2326 * where adding another extent that would squash into the last array entry 2327 * would result in an incorrect range reported to the client) 2328 */ 2329 static int nbd_extent_array_add(NBDExtentArray *ea, 2330 uint64_t length, uint32_t flags) 2331 { 2332 assert(ea->can_add); 2333 2334 if (!length) { 2335 return 0; 2336 } 2337 if (!ea->extended) { 2338 assert(length <= UINT32_MAX); 2339 } 2340 2341 /* Extend previous extent if flags are the same */ 2342 if (ea->count > 0 && flags == ea->extents[ea->count - 1].flags) { 2343 uint64_t sum = length + ea->extents[ea->count - 1].length; 2344 2345 /* 2346 * sum cannot overflow: the block layer bounds image size at 2347 * 2^63, and ea->extents[].length comes from the block layer. 2348 */ 2349 assert(sum >= length); 2350 if (sum <= UINT32_MAX || ea->extended) { 2351 ea->extents[ea->count - 1].length = sum; 2352 ea->total_length += length; 2353 return 0; 2354 } 2355 } 2356 2357 if (ea->count >= ea->nb_alloc) { 2358 ea->can_add = false; 2359 return -1; 2360 } 2361 2362 ea->total_length += length; 2363 ea->extents[ea->count] = (NBDExtent64) {.length = length, .flags = flags}; 2364 ea->count++; 2365 2366 return 0; 2367 } 2368 2369 static int coroutine_fn blockstatus_to_extents(BlockBackend *blk, 2370 uint64_t offset, uint64_t bytes, 2371 NBDExtentArray *ea) 2372 { 2373 while (bytes) { 2374 uint32_t flags; 2375 int64_t num; 2376 int ret = blk_co_block_status_above(blk, NULL, offset, bytes, &num, 2377 NULL, NULL); 2378 2379 if (ret < 0) { 2380 return ret; 2381 } 2382 2383 flags = (ret & BDRV_BLOCK_DATA ? 0 : NBD_STATE_HOLE) | 2384 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 2385 2386 if (nbd_extent_array_add(ea, num, flags) < 0) { 2387 return 0; 2388 } 2389 2390 offset += num; 2391 bytes -= num; 2392 } 2393 2394 return 0; 2395 } 2396 2397 static int coroutine_fn blockalloc_to_extents(BlockBackend *blk, 2398 uint64_t offset, uint64_t bytes, 2399 NBDExtentArray *ea) 2400 { 2401 while (bytes) { 2402 int64_t num; 2403 int ret = blk_co_is_allocated_above(blk, NULL, false, offset, bytes, 2404 &num); 2405 2406 if (ret < 0) { 2407 return ret; 2408 } 2409 2410 if (nbd_extent_array_add(ea, num, ret) < 0) { 2411 return 0; 2412 } 2413 2414 offset += num; 2415 bytes -= num; 2416 } 2417 2418 return 0; 2419 } 2420 2421 /* 2422 * nbd_co_send_extents 2423 * 2424 * @ea is converted to BE by the function 2425 * @last controls whether NBD_REPLY_FLAG_DONE is sent. 2426 */ 2427 static int coroutine_fn 2428 nbd_co_send_extents(NBDClient *client, NBDRequest *request, NBDExtentArray *ea, 2429 bool last, uint32_t context_id, Error **errp) 2430 { 2431 NBDReply hdr; 2432 NBDStructuredMeta meta; 2433 NBDExtendedMeta meta_ext; 2434 g_autofree NBDExtent32 *extents = NULL; 2435 uint16_t type; 2436 struct iovec iov[] = { {.iov_base = &hdr}, {0}, {0} }; 2437 2438 if (client->mode >= NBD_MODE_EXTENDED) { 2439 type = NBD_REPLY_TYPE_BLOCK_STATUS_EXT; 2440 2441 iov[1].iov_base = &meta_ext; 2442 iov[1].iov_len = sizeof(meta_ext); 2443 stl_be_p(&meta_ext.context_id, context_id); 2444 stl_be_p(&meta_ext.count, ea->count); 2445 2446 nbd_extent_array_convert_to_be(ea); 2447 iov[2].iov_base = ea->extents; 2448 iov[2].iov_len = ea->count * sizeof(ea->extents[0]); 2449 } else { 2450 type = NBD_REPLY_TYPE_BLOCK_STATUS; 2451 2452 iov[1].iov_base = &meta; 2453 iov[1].iov_len = sizeof(meta); 2454 stl_be_p(&meta.context_id, context_id); 2455 2456 extents = nbd_extent_array_convert_to_narrow(ea); 2457 iov[2].iov_base = extents; 2458 iov[2].iov_len = ea->count * sizeof(extents[0]); 2459 } 2460 2461 trace_nbd_co_send_extents(request->cookie, ea->count, context_id, 2462 ea->total_length, last); 2463 set_be_chunk(client, iov, 3, last ? NBD_REPLY_FLAG_DONE : 0, type, 2464 request); 2465 2466 return nbd_co_send_iov(client, iov, 3, errp); 2467 } 2468 2469 /* Get block status from the exported device and send it to the client */ 2470 static int 2471 coroutine_fn nbd_co_send_block_status(NBDClient *client, NBDRequest *request, 2472 BlockBackend *blk, uint64_t offset, 2473 uint64_t length, bool dont_fragment, 2474 bool last, uint32_t context_id, 2475 Error **errp) 2476 { 2477 int ret; 2478 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2479 g_autoptr(NBDExtentArray) ea = 2480 nbd_extent_array_new(nb_extents, client->mode); 2481 2482 if (context_id == NBD_META_ID_BASE_ALLOCATION) { 2483 ret = blockstatus_to_extents(blk, offset, length, ea); 2484 } else { 2485 ret = blockalloc_to_extents(blk, offset, length, ea); 2486 } 2487 if (ret < 0) { 2488 return nbd_co_send_chunk_error(client, request, -ret, 2489 "can't get block status", errp); 2490 } 2491 2492 return nbd_co_send_extents(client, request, ea, last, context_id, errp); 2493 } 2494 2495 /* Populate @ea from a dirty bitmap. */ 2496 static void bitmap_to_extents(BdrvDirtyBitmap *bitmap, 2497 uint64_t offset, uint64_t length, 2498 NBDExtentArray *es) 2499 { 2500 int64_t start, dirty_start, dirty_count; 2501 int64_t end = offset + length; 2502 bool full = false; 2503 int64_t bound = es->extended ? INT64_MAX : INT32_MAX; 2504 2505 bdrv_dirty_bitmap_lock(bitmap); 2506 2507 for (start = offset; 2508 bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, bound, 2509 &dirty_start, &dirty_count); 2510 start = dirty_start + dirty_count) 2511 { 2512 if ((nbd_extent_array_add(es, dirty_start - start, 0) < 0) || 2513 (nbd_extent_array_add(es, dirty_count, NBD_STATE_DIRTY) < 0)) 2514 { 2515 full = true; 2516 break; 2517 } 2518 } 2519 2520 if (!full) { 2521 /* last non dirty extent, nothing to do if array is now full */ 2522 (void) nbd_extent_array_add(es, end - start, 0); 2523 } 2524 2525 bdrv_dirty_bitmap_unlock(bitmap); 2526 } 2527 2528 static int coroutine_fn nbd_co_send_bitmap(NBDClient *client, 2529 NBDRequest *request, 2530 BdrvDirtyBitmap *bitmap, 2531 uint64_t offset, 2532 uint64_t length, bool dont_fragment, 2533 bool last, uint32_t context_id, 2534 Error **errp) 2535 { 2536 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2537 g_autoptr(NBDExtentArray) ea = 2538 nbd_extent_array_new(nb_extents, client->mode); 2539 2540 bitmap_to_extents(bitmap, offset, length, ea); 2541 2542 return nbd_co_send_extents(client, request, ea, last, context_id, errp); 2543 } 2544 2545 /* 2546 * nbd_co_block_status_payload_read 2547 * Called when a client wants a subset of negotiated contexts via a 2548 * BLOCK_STATUS payload. Check the payload for valid length and 2549 * contents. On success, return 0 with request updated to effective 2550 * length. If request was invalid but all payload consumed, return 0 2551 * with request->len and request->contexts->count set to 0 (which will 2552 * trigger an appropriate NBD_EINVAL response later on). Return 2553 * negative errno if the payload was not fully consumed. 2554 */ 2555 static int 2556 nbd_co_block_status_payload_read(NBDClient *client, NBDRequest *request, 2557 Error **errp) 2558 { 2559 uint64_t payload_len = request->len; 2560 g_autofree char *buf = NULL; 2561 size_t count, i, nr_bitmaps; 2562 uint32_t id; 2563 2564 if (payload_len > NBD_MAX_BUFFER_SIZE) { 2565 error_setg(errp, "len (%" PRIu64 ") is larger than max len (%u)", 2566 request->len, NBD_MAX_BUFFER_SIZE); 2567 return -EINVAL; 2568 } 2569 2570 assert(client->contexts.exp == client->exp); 2571 nr_bitmaps = client->exp->nr_export_bitmaps; 2572 request->contexts = g_new0(NBDMetaContexts, 1); 2573 request->contexts->exp = client->exp; 2574 2575 if (payload_len % sizeof(uint32_t) || 2576 payload_len < sizeof(NBDBlockStatusPayload) || 2577 payload_len > (sizeof(NBDBlockStatusPayload) + 2578 sizeof(id) * client->contexts.count)) { 2579 goto skip; 2580 } 2581 2582 buf = g_malloc(payload_len); 2583 if (nbd_read(client->ioc, buf, payload_len, 2584 "CMD_BLOCK_STATUS data", errp) < 0) { 2585 return -EIO; 2586 } 2587 trace_nbd_co_receive_request_payload_received(request->cookie, 2588 payload_len); 2589 request->contexts->bitmaps = g_new0(bool, nr_bitmaps); 2590 count = (payload_len - sizeof(NBDBlockStatusPayload)) / sizeof(id); 2591 payload_len = 0; 2592 2593 for (i = 0; i < count; i++) { 2594 id = ldl_be_p(buf + sizeof(NBDBlockStatusPayload) + sizeof(id) * i); 2595 if (id == NBD_META_ID_BASE_ALLOCATION) { 2596 if (!client->contexts.base_allocation || 2597 request->contexts->base_allocation) { 2598 goto skip; 2599 } 2600 request->contexts->base_allocation = true; 2601 } else if (id == NBD_META_ID_ALLOCATION_DEPTH) { 2602 if (!client->contexts.allocation_depth || 2603 request->contexts->allocation_depth) { 2604 goto skip; 2605 } 2606 request->contexts->allocation_depth = true; 2607 } else { 2608 unsigned idx = id - NBD_META_ID_DIRTY_BITMAP; 2609 2610 if (idx >= nr_bitmaps || !client->contexts.bitmaps[idx] || 2611 request->contexts->bitmaps[idx]) { 2612 goto skip; 2613 } 2614 request->contexts->bitmaps[idx] = true; 2615 } 2616 } 2617 2618 request->len = ldq_be_p(buf); 2619 request->contexts->count = count; 2620 return 0; 2621 2622 skip: 2623 trace_nbd_co_receive_block_status_payload_compliance(request->from, 2624 request->len); 2625 request->len = request->contexts->count = 0; 2626 return nbd_drop(client->ioc, payload_len, errp); 2627 } 2628 2629 /* nbd_co_receive_request 2630 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2631 * connection right away, -EAGAIN to indicate we were interrupted and the 2632 * channel should be quiesced, and any other negative value to report an error 2633 * to the client (although the caller may still need to disconnect after 2634 * reporting the error). 2635 */ 2636 static int coroutine_fn nbd_co_receive_request(NBDRequestData *req, 2637 NBDRequest *request, 2638 Error **errp) 2639 { 2640 NBDClient *client = req->client; 2641 bool extended_with_payload; 2642 bool check_length = false; 2643 bool check_rofs = false; 2644 bool allocate_buffer = false; 2645 bool payload_okay = false; 2646 uint64_t payload_len = 0; 2647 int valid_flags = NBD_CMD_FLAG_FUA; 2648 int ret; 2649 2650 g_assert(qemu_in_coroutine()); 2651 ret = nbd_receive_request(client, request, errp); 2652 if (ret < 0) { 2653 return ret; 2654 } 2655 2656 trace_nbd_co_receive_request_decode_type(request->cookie, request->type, 2657 nbd_cmd_lookup(request->type)); 2658 extended_with_payload = client->mode >= NBD_MODE_EXTENDED && 2659 request->flags & NBD_CMD_FLAG_PAYLOAD_LEN; 2660 if (extended_with_payload) { 2661 payload_len = request->len; 2662 check_length = true; 2663 } 2664 2665 switch (request->type) { 2666 case NBD_CMD_DISC: 2667 /* Special case: we're going to disconnect without a reply, 2668 * whether or not flags, from, or len are bogus */ 2669 req->complete = true; 2670 return -EIO; 2671 2672 case NBD_CMD_READ: 2673 if (client->mode >= NBD_MODE_STRUCTURED) { 2674 valid_flags |= NBD_CMD_FLAG_DF; 2675 } 2676 check_length = true; 2677 allocate_buffer = true; 2678 break; 2679 2680 case NBD_CMD_WRITE: 2681 if (client->mode >= NBD_MODE_EXTENDED) { 2682 if (!extended_with_payload) { 2683 /* The client is noncompliant. Trace it, but proceed. */ 2684 trace_nbd_co_receive_ext_payload_compliance(request->from, 2685 request->len); 2686 } 2687 valid_flags |= NBD_CMD_FLAG_PAYLOAD_LEN; 2688 } 2689 payload_okay = true; 2690 payload_len = request->len; 2691 check_length = true; 2692 allocate_buffer = true; 2693 check_rofs = true; 2694 break; 2695 2696 case NBD_CMD_FLUSH: 2697 break; 2698 2699 case NBD_CMD_TRIM: 2700 check_rofs = true; 2701 break; 2702 2703 case NBD_CMD_CACHE: 2704 check_length = true; 2705 break; 2706 2707 case NBD_CMD_WRITE_ZEROES: 2708 valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO; 2709 check_rofs = true; 2710 break; 2711 2712 case NBD_CMD_BLOCK_STATUS: 2713 if (extended_with_payload) { 2714 ret = nbd_co_block_status_payload_read(client, request, errp); 2715 if (ret < 0) { 2716 return ret; 2717 } 2718 /* payload now consumed */ 2719 check_length = false; 2720 payload_len = 0; 2721 valid_flags |= NBD_CMD_FLAG_PAYLOAD_LEN; 2722 } else { 2723 request->contexts = &client->contexts; 2724 } 2725 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2726 break; 2727 2728 default: 2729 /* Unrecognized, will fail later */ 2730 ; 2731 } 2732 2733 /* Payload and buffer handling. */ 2734 if (!payload_len) { 2735 req->complete = true; 2736 } 2737 if (check_length && request->len > NBD_MAX_BUFFER_SIZE) { 2738 /* READ, WRITE, CACHE */ 2739 error_setg(errp, "len (%" PRIu64 ") is larger than max len (%u)", 2740 request->len, NBD_MAX_BUFFER_SIZE); 2741 return -EINVAL; 2742 } 2743 if (payload_len && !payload_okay) { 2744 /* 2745 * For now, we don't support payloads on other commands; but 2746 * we can keep the connection alive by ignoring the payload. 2747 * We will fail the command later with NBD_EINVAL for the use 2748 * of an unsupported flag (and not for access beyond bounds). 2749 */ 2750 assert(request->type != NBD_CMD_WRITE); 2751 request->len = 0; 2752 } 2753 if (allocate_buffer) { 2754 /* READ, WRITE */ 2755 req->data = blk_try_blockalign(client->exp->common.blk, 2756 request->len); 2757 if (req->data == NULL) { 2758 error_setg(errp, "No memory"); 2759 return -ENOMEM; 2760 } 2761 } 2762 if (payload_len) { 2763 if (payload_okay) { 2764 /* WRITE */ 2765 assert(req->data); 2766 ret = nbd_read(client->ioc, req->data, payload_len, 2767 "CMD_WRITE data", errp); 2768 } else { 2769 ret = nbd_drop(client->ioc, payload_len, errp); 2770 } 2771 if (ret < 0) { 2772 return -EIO; 2773 } 2774 req->complete = true; 2775 trace_nbd_co_receive_request_payload_received(request->cookie, 2776 payload_len); 2777 } 2778 2779 /* Sanity checks. */ 2780 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && check_rofs) { 2781 /* WRITE, TRIM, WRITE_ZEROES */ 2782 error_setg(errp, "Export is read-only"); 2783 return -EROFS; 2784 } 2785 if (request->from > client->exp->size || 2786 request->len > client->exp->size - request->from) { 2787 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu64 2788 ", Size: %" PRIu64, request->from, request->len, 2789 client->exp->size); 2790 return (request->type == NBD_CMD_WRITE || 2791 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2792 } 2793 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len, 2794 client->check_align)) { 2795 /* 2796 * The block layer gracefully handles unaligned requests, but 2797 * it's still worth tracing client non-compliance 2798 */ 2799 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type), 2800 request->from, 2801 request->len, 2802 client->check_align); 2803 } 2804 if (request->flags & ~valid_flags) { 2805 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2806 nbd_cmd_lookup(request->type), request->flags); 2807 return -EINVAL; 2808 } 2809 2810 return 0; 2811 } 2812 2813 /* Send simple reply without a payload, or a structured error 2814 * @error_msg is ignored if @ret >= 0 2815 * Returns 0 if connection is still live, -errno on failure to talk to client 2816 */ 2817 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2818 NBDRequest *request, 2819 int ret, 2820 const char *error_msg, 2821 Error **errp) 2822 { 2823 if (client->mode >= NBD_MODE_STRUCTURED && ret < 0) { 2824 return nbd_co_send_chunk_error(client, request, -ret, error_msg, errp); 2825 } else if (client->mode >= NBD_MODE_EXTENDED) { 2826 return nbd_co_send_chunk_done(client, request, errp); 2827 } else { 2828 return nbd_co_send_simple_reply(client, request, ret < 0 ? -ret : 0, 2829 NULL, 0, errp); 2830 } 2831 } 2832 2833 /* Handle NBD_CMD_READ request. 2834 * Return -errno if sending fails. Other errors are reported directly to the 2835 * client as an error reply. */ 2836 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2837 uint8_t *data, Error **errp) 2838 { 2839 int ret; 2840 NBDExport *exp = client->exp; 2841 2842 assert(request->type == NBD_CMD_READ); 2843 assert(request->len <= NBD_MAX_BUFFER_SIZE); 2844 2845 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2846 if (request->flags & NBD_CMD_FLAG_FUA) { 2847 ret = blk_co_flush(exp->common.blk); 2848 if (ret < 0) { 2849 return nbd_send_generic_reply(client, request, ret, 2850 "flush failed", errp); 2851 } 2852 } 2853 2854 if (client->mode >= NBD_MODE_STRUCTURED && 2855 !(request->flags & NBD_CMD_FLAG_DF) && request->len) 2856 { 2857 return nbd_co_send_sparse_read(client, request, request->from, 2858 data, request->len, errp); 2859 } 2860 2861 ret = blk_co_pread(exp->common.blk, request->from, request->len, data, 0); 2862 if (ret < 0) { 2863 return nbd_send_generic_reply(client, request, ret, 2864 "reading from file failed", errp); 2865 } 2866 2867 if (client->mode >= NBD_MODE_STRUCTURED) { 2868 if (request->len) { 2869 return nbd_co_send_chunk_read(client, request, request->from, data, 2870 request->len, true, errp); 2871 } else { 2872 return nbd_co_send_chunk_done(client, request, errp); 2873 } 2874 } else { 2875 return nbd_co_send_simple_reply(client, request, 0, 2876 data, request->len, errp); 2877 } 2878 } 2879 2880 /* 2881 * nbd_do_cmd_cache 2882 * 2883 * Handle NBD_CMD_CACHE request. 2884 * Return -errno if sending fails. Other errors are reported directly to the 2885 * client as an error reply. 2886 */ 2887 static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request, 2888 Error **errp) 2889 { 2890 int ret; 2891 NBDExport *exp = client->exp; 2892 2893 assert(request->type == NBD_CMD_CACHE); 2894 assert(request->len <= NBD_MAX_BUFFER_SIZE); 2895 2896 ret = blk_co_preadv(exp->common.blk, request->from, request->len, 2897 NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH); 2898 2899 return nbd_send_generic_reply(client, request, ret, 2900 "caching data failed", errp); 2901 } 2902 2903 /* Handle NBD request. 2904 * Return -errno if sending fails. Other errors are reported directly to the 2905 * client as an error reply. */ 2906 static coroutine_fn int nbd_handle_request(NBDClient *client, 2907 NBDRequest *request, 2908 uint8_t *data, Error **errp) 2909 { 2910 int ret; 2911 int flags; 2912 NBDExport *exp = client->exp; 2913 char *msg; 2914 size_t i; 2915 2916 switch (request->type) { 2917 case NBD_CMD_CACHE: 2918 return nbd_do_cmd_cache(client, request, errp); 2919 2920 case NBD_CMD_READ: 2921 return nbd_do_cmd_read(client, request, data, errp); 2922 2923 case NBD_CMD_WRITE: 2924 flags = 0; 2925 if (request->flags & NBD_CMD_FLAG_FUA) { 2926 flags |= BDRV_REQ_FUA; 2927 } 2928 assert(request->len <= NBD_MAX_BUFFER_SIZE); 2929 ret = blk_co_pwrite(exp->common.blk, request->from, request->len, data, 2930 flags); 2931 return nbd_send_generic_reply(client, request, ret, 2932 "writing to file failed", errp); 2933 2934 case NBD_CMD_WRITE_ZEROES: 2935 flags = 0; 2936 if (request->flags & NBD_CMD_FLAG_FUA) { 2937 flags |= BDRV_REQ_FUA; 2938 } 2939 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2940 flags |= BDRV_REQ_MAY_UNMAP; 2941 } 2942 if (request->flags & NBD_CMD_FLAG_FAST_ZERO) { 2943 flags |= BDRV_REQ_NO_FALLBACK; 2944 } 2945 ret = blk_co_pwrite_zeroes(exp->common.blk, request->from, request->len, 2946 flags); 2947 return nbd_send_generic_reply(client, request, ret, 2948 "writing to file failed", errp); 2949 2950 case NBD_CMD_DISC: 2951 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2952 abort(); 2953 2954 case NBD_CMD_FLUSH: 2955 ret = blk_co_flush(exp->common.blk); 2956 return nbd_send_generic_reply(client, request, ret, 2957 "flush failed", errp); 2958 2959 case NBD_CMD_TRIM: 2960 ret = blk_co_pdiscard(exp->common.blk, request->from, request->len); 2961 if (ret >= 0 && request->flags & NBD_CMD_FLAG_FUA) { 2962 ret = blk_co_flush(exp->common.blk); 2963 } 2964 return nbd_send_generic_reply(client, request, ret, 2965 "discard failed", errp); 2966 2967 case NBD_CMD_BLOCK_STATUS: 2968 assert(request->contexts); 2969 assert(client->mode >= NBD_MODE_EXTENDED || 2970 request->len <= UINT32_MAX); 2971 if (request->contexts->count) { 2972 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2973 int contexts_remaining = request->contexts->count; 2974 2975 if (!request->len) { 2976 return nbd_send_generic_reply(client, request, -EINVAL, 2977 "need non-zero length", errp); 2978 } 2979 if (request->contexts->base_allocation) { 2980 ret = nbd_co_send_block_status(client, request, 2981 exp->common.blk, 2982 request->from, 2983 request->len, dont_fragment, 2984 !--contexts_remaining, 2985 NBD_META_ID_BASE_ALLOCATION, 2986 errp); 2987 if (ret < 0) { 2988 return ret; 2989 } 2990 } 2991 2992 if (request->contexts->allocation_depth) { 2993 ret = nbd_co_send_block_status(client, request, 2994 exp->common.blk, 2995 request->from, request->len, 2996 dont_fragment, 2997 !--contexts_remaining, 2998 NBD_META_ID_ALLOCATION_DEPTH, 2999 errp); 3000 if (ret < 0) { 3001 return ret; 3002 } 3003 } 3004 3005 assert(request->contexts->exp == client->exp); 3006 for (i = 0; i < client->exp->nr_export_bitmaps; i++) { 3007 if (!request->contexts->bitmaps[i]) { 3008 continue; 3009 } 3010 ret = nbd_co_send_bitmap(client, request, 3011 client->exp->export_bitmaps[i], 3012 request->from, request->len, 3013 dont_fragment, !--contexts_remaining, 3014 NBD_META_ID_DIRTY_BITMAP + i, errp); 3015 if (ret < 0) { 3016 return ret; 3017 } 3018 } 3019 3020 assert(!contexts_remaining); 3021 3022 return 0; 3023 } else if (client->contexts.count) { 3024 return nbd_send_generic_reply(client, request, -EINVAL, 3025 "CMD_BLOCK_STATUS payload not valid", 3026 errp); 3027 } else { 3028 return nbd_send_generic_reply(client, request, -EINVAL, 3029 "CMD_BLOCK_STATUS not negotiated", 3030 errp); 3031 } 3032 3033 default: 3034 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 3035 request->type); 3036 ret = nbd_send_generic_reply(client, request, -EINVAL, msg, 3037 errp); 3038 g_free(msg); 3039 return ret; 3040 } 3041 } 3042 3043 /* Owns a reference to the NBDClient passed as opaque. */ 3044 static coroutine_fn void nbd_trip(void *opaque) 3045 { 3046 NBDRequestData *req = opaque; 3047 NBDClient *client = req->client; 3048 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 3049 int ret; 3050 Error *local_err = NULL; 3051 3052 /* 3053 * Note that nbd_client_put() and client_close() must be called from the 3054 * main loop thread. Use aio_co_reschedule_self() to switch AioContext 3055 * before calling these functions. 3056 */ 3057 3058 trace_nbd_trip(); 3059 3060 qemu_mutex_lock(&client->lock); 3061 3062 if (client->closing) { 3063 goto done; 3064 } 3065 3066 if (client->quiescing) { 3067 /* 3068 * We're switching between AIO contexts. Don't attempt to receive a new 3069 * request and kick the main context which may be waiting for us. 3070 */ 3071 client->recv_coroutine = NULL; 3072 aio_wait_kick(); 3073 goto done; 3074 } 3075 3076 /* 3077 * nbd_co_receive_request() returns -EAGAIN when nbd_drained_begin() has 3078 * set client->quiescing but by the time we get back nbd_drained_end() may 3079 * have already cleared client->quiescing. In that case we try again 3080 * because nothing else will spawn an nbd_trip() coroutine until we set 3081 * client->recv_coroutine = NULL further down. 3082 */ 3083 do { 3084 assert(client->recv_coroutine == qemu_coroutine_self()); 3085 qemu_mutex_unlock(&client->lock); 3086 ret = nbd_co_receive_request(req, &request, &local_err); 3087 qemu_mutex_lock(&client->lock); 3088 } while (ret == -EAGAIN && !client->quiescing); 3089 3090 client->recv_coroutine = NULL; 3091 3092 if (client->closing) { 3093 /* 3094 * The client may be closed when we are blocked in 3095 * nbd_co_receive_request() 3096 */ 3097 goto done; 3098 } 3099 3100 if (ret == -EAGAIN) { 3101 goto done; 3102 } 3103 3104 nbd_client_receive_next_request(client); 3105 3106 if (ret == -EIO) { 3107 goto disconnect; 3108 } 3109 3110 qemu_mutex_unlock(&client->lock); 3111 qio_channel_set_cork(client->ioc, true); 3112 3113 if (ret < 0) { 3114 /* It wasn't -EIO, so, according to nbd_co_receive_request() 3115 * semantics, we should return the error to the client. */ 3116 Error *export_err = local_err; 3117 3118 local_err = NULL; 3119 ret = nbd_send_generic_reply(client, &request, -EINVAL, 3120 error_get_pretty(export_err), &local_err); 3121 error_free(export_err); 3122 } else { 3123 ret = nbd_handle_request(client, &request, req->data, &local_err); 3124 } 3125 if (request.contexts && request.contexts != &client->contexts) { 3126 assert(request.type == NBD_CMD_BLOCK_STATUS); 3127 g_free(request.contexts->bitmaps); 3128 g_free(request.contexts); 3129 } 3130 3131 qio_channel_set_cork(client->ioc, false); 3132 qemu_mutex_lock(&client->lock); 3133 3134 if (ret < 0) { 3135 error_prepend(&local_err, "Failed to send reply: "); 3136 goto disconnect; 3137 } 3138 3139 /* 3140 * We must disconnect after NBD_CMD_WRITE or BLOCK_STATUS with 3141 * payload if we did not read the payload. 3142 */ 3143 if (!req->complete) { 3144 error_setg(&local_err, "Request handling failed in intermediate state"); 3145 goto disconnect; 3146 } 3147 3148 done: 3149 nbd_request_put(req); 3150 3151 qemu_mutex_unlock(&client->lock); 3152 3153 if (!nbd_client_put_nonzero(client)) { 3154 aio_co_reschedule_self(qemu_get_aio_context()); 3155 nbd_client_put(client); 3156 } 3157 return; 3158 3159 disconnect: 3160 if (local_err) { 3161 error_reportf_err(local_err, "Disconnect client, due to: "); 3162 } 3163 3164 nbd_request_put(req); 3165 qemu_mutex_unlock(&client->lock); 3166 3167 aio_co_reschedule_self(qemu_get_aio_context()); 3168 client_close(client, true); 3169 nbd_client_put(client); 3170 } 3171 3172 /* 3173 * Runs in export AioContext and main loop thread. Caller must hold 3174 * client->lock. 3175 */ 3176 static void nbd_client_receive_next_request(NBDClient *client) 3177 { 3178 NBDRequestData *req; 3179 3180 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS && 3181 !client->quiescing) { 3182 nbd_client_get(client); 3183 req = nbd_request_get(client); 3184 client->recv_coroutine = qemu_coroutine_create(nbd_trip, req); 3185 aio_co_schedule(client->exp->common.ctx, client->recv_coroutine); 3186 } 3187 } 3188 3189 static void nbd_handshake_timer_cb(void *opaque) 3190 { 3191 QIOChannel *ioc = opaque; 3192 3193 trace_nbd_handshake_timer_cb(); 3194 qio_channel_shutdown(ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL); 3195 } 3196 3197 static coroutine_fn void nbd_co_client_start(void *opaque) 3198 { 3199 NBDClient *client = opaque; 3200 Error *local_err = NULL; 3201 QEMUTimer *handshake_timer = NULL; 3202 3203 qemu_co_mutex_init(&client->send_lock); 3204 3205 /* 3206 * Create a timer to bound the time spent in negotiation. If the 3207 * timer expires, it is likely nbd_negotiate will fail because the 3208 * socket was shutdown. 3209 */ 3210 if (client->handshake_max_secs > 0) { 3211 handshake_timer = aio_timer_new(qemu_get_aio_context(), 3212 QEMU_CLOCK_REALTIME, 3213 SCALE_NS, 3214 nbd_handshake_timer_cb, 3215 client->sioc); 3216 timer_mod(handshake_timer, 3217 qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + 3218 client->handshake_max_secs * NANOSECONDS_PER_SECOND); 3219 } 3220 3221 if (nbd_negotiate(client, &local_err)) { 3222 if (local_err) { 3223 error_report_err(local_err); 3224 } 3225 timer_free(handshake_timer); 3226 client_close(client, false); 3227 return; 3228 } 3229 3230 timer_free(handshake_timer); 3231 WITH_QEMU_LOCK_GUARD(&client->lock) { 3232 nbd_client_receive_next_request(client); 3233 } 3234 } 3235 3236 /* 3237 * Create a new client listener using the given channel @sioc and @owner. 3238 * Begin servicing it in a coroutine. When the connection closes, call 3239 * @close_fn with an indication of whether the client completed negotiation 3240 * within @handshake_max_secs seconds (0 for unbounded). 3241 */ 3242 void nbd_client_new(QIOChannelSocket *sioc, 3243 uint32_t handshake_max_secs, 3244 QCryptoTLSCreds *tlscreds, 3245 const char *tlsauthz, 3246 void (*close_fn)(NBDClient *, bool), 3247 void *owner) 3248 { 3249 NBDClient *client; 3250 Coroutine *co; 3251 3252 client = g_new0(NBDClient, 1); 3253 qemu_mutex_init(&client->lock); 3254 client->refcount = 1; 3255 client->tlscreds = tlscreds; 3256 if (tlscreds) { 3257 object_ref(OBJECT(client->tlscreds)); 3258 } 3259 client->tlsauthz = g_strdup(tlsauthz); 3260 client->handshake_max_secs = handshake_max_secs; 3261 client->sioc = sioc; 3262 qio_channel_set_delay(QIO_CHANNEL(sioc), false); 3263 object_ref(OBJECT(client->sioc)); 3264 client->ioc = QIO_CHANNEL(sioc); 3265 object_ref(OBJECT(client->ioc)); 3266 client->close_fn = close_fn; 3267 client->owner = owner; 3268 3269 co = qemu_coroutine_create(nbd_co_client_start, client); 3270 qemu_coroutine_enter(co); 3271 } 3272 3273 void * 3274 nbd_client_owner(NBDClient *client) 3275 { 3276 return client->owner; 3277 } 3278