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1 /*

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 */

20 #include "qemu/osdep.h"

21 #include "qapi/error.h"

22 #include "trace.h"

23 #include "nbd-internal.h"

25 #define NBD_META_ID_BASE_ALLOCATION 0

26 #define NBD_META_ID_DIRTY_BITMAP 1

28 /* NBD_MAX_BITMAP_EXTENTS: 1 mb of extents data. An empirical

29 * constant. If an increase is needed, note that the NBD protocol

30 * recommends no larger than 32 mb, so that the client won't consider

31 * the reply as a denial of service attack. */

32 #define NBD_MAX_BITMAP_EXTENTS (0x100000 / 8)

34 static int system_errno_to_nbd_errno(int err)

35 {

36 switch (err) {

37 case 0:

38 return NBD_SUCCESS;

39 case EPERM:

40 case EROFS:

41 return NBD_EPERM;

42 case EIO:

43 return NBD_EIO;

44 case ENOMEM:

45 return NBD_ENOMEM;

46 #ifdef EDQUOT

47 case EDQUOT:

48 #endif

49 case EFBIG:

50 case ENOSPC:

51 return NBD_ENOSPC;

52 case EOVERFLOW:

53 return NBD_EOVERFLOW;

54 case ESHUTDOWN:

55 return NBD_ESHUTDOWN;

56 case EINVAL:

57 default:

58 return NBD_EINVAL;

59 }

60 }

62 /* Definitions for opaque data types */

64 typedef struct NBDRequestData NBDRequestData;

66 struct NBDRequestData {

67 QSIMPLEQ_ENTRY(NBDRequestData) entry;

68 NBDClient *client;

69 uint8_t *data;

70 bool complete;

71 };

73 struct NBDExport {

74 int refcount;

75 void (*close)(NBDExport *exp);

77 BlockBackend *blk;

78 char *name;

79 char *description;

80 uint64_t dev_offset;

81 uint64_t size;

82 uint16_t nbdflags;

83 QTAILQ_HEAD(, NBDClient) clients;

84 QTAILQ_ENTRY(NBDExport) next;

86 AioContext *ctx;

88 BlockBackend *eject_notifier_blk;

89 Notifier eject_notifier;

91 BdrvDirtyBitmap *export_bitmap;

92 char *export_bitmap_context;

93 };

95 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);

97 /* NBDExportMetaContexts represents a list of contexts to be exported,

98 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for

99 * NBD_OPT_LIST_META_CONTEXT. */

100 typedef struct NBDExportMetaContexts {

101 NBDExport *exp;

102 bool valid; /* means that negotiation of the option finished without

103 errors */

104 bool base_allocation; /* export base:allocation context (block status) */

105 bool bitmap; /* export qemu:dirty-bitmap:<export bitmap name> */

106 } NBDExportMetaContexts;

107

108 struct NBDClient {

109 int refcount;

110 void (*close_fn)(NBDClient *client, bool negotiated);

111

112 NBDExport *exp;

113 QCryptoTLSCreds *tlscreds;

114 char *tlsauthz;

115 QIOChannelSocket *sioc; /* The underlying data channel */

116 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */

117

118 Coroutine *recv_coroutine;

119

120 CoMutex send_lock;

121 Coroutine *send_coroutine;

122

123 QTAILQ_ENTRY(NBDClient) next;

124 int nb_requests;

125 bool closing;

126

127 bool structured_reply;

128 NBDExportMetaContexts export_meta;

129

130 uint32_t opt; /* Current option being negotiated */

131 uint32_t optlen; /* remaining length of data in ioc for the option being

132 negotiated now */

133 };

134

135 static void nbd_client_receive_next_request(NBDClient *client);

136

137 /* Basic flow for negotiation

138

139 Server Client

140 Negotiate

141

142 or

143

144 Server Client

145 Negotiate #1

146 Option

147 Negotiate #2

148

149 ----

150

151 followed by

152

153 Server Client

154 Request

155 Response

156 Request

157 Response

158 ...

159 ...

160 Request (type == 2)

161

162 */

163

164 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option,

165 uint32_t type, uint32_t length)

166 {

167 stq_be_p(&rep->magic, NBD_REP_MAGIC);

168 stl_be_p(&rep->option, option);

169 stl_be_p(&rep->type, type);

170 stl_be_p(&rep->length, length);

171 }

172

173 /* Send a reply header, including length, but no payload.

174 * Return -errno on error, 0 on success. */

175 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type,

176 uint32_t len, Error **errp)

177 {

178 NBDOptionReply rep;

179

180 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt),

181 type, nbd_rep_lookup(type), len);

182

183 assert(len < NBD_MAX_BUFFER_SIZE);

184

185 set_be_option_rep(&rep, client->opt, type, len);

186 return nbd_write(client->ioc, &rep, sizeof(rep), errp);

187 }

188

189 /* Send a reply header with default 0 length.

190 * Return -errno on error, 0 on success. */

191 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type,

192 Error **errp)

193 {

194 return nbd_negotiate_send_rep_len(client, type, 0, errp);

195 }

196

197 /* Send an error reply.

198 * Return -errno on error, 0 on success. */

199 static int GCC_FMT_ATTR(4, 0)

200 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,

201 Error **errp, const char *fmt, va_list va)

202 {

203 char *msg;

204 int ret;

205 size_t len;

206

207 msg = g_strdup_vprintf(fmt, va);

208 len = strlen(msg);

209 assert(len < 4096);

210 trace_nbd_negotiate_send_rep_err(msg);

211 ret = nbd_negotiate_send_rep_len(client, type, len, errp);

212 if (ret < 0) {

213 goto out;

214 }

215 if (nbd_write(client->ioc, msg, len, errp) < 0) {

216 error_prepend(errp, "write failed (error message): ");

217 ret = -EIO;

218 } else {

219 ret = 0;

220 }

221

222 out:

223 g_free(msg);

224 return ret;

225 }

226

227 /* Send an error reply.

228 * Return -errno on error, 0 on success. */

229 static int GCC_FMT_ATTR(4, 5)

230 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type,

231 Error **errp, const char *fmt, ...)

232 {

233 va_list va;

234 int ret;

235

236 va_start(va, fmt);

237 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);

238 va_end(va);

239 return ret;

240 }

241

242 /* Drop remainder of the current option, and send a reply with the

243 * given error type and message. Return -errno on read or write

244 * failure; or 0 if connection is still live. */

245 static int GCC_FMT_ATTR(4, 0)

246 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp,

247 const char *fmt, va_list va)

248 {

249 int ret = nbd_drop(client->ioc, client->optlen, errp);

250

251 client->optlen = 0;

252 if (!ret) {

253 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);

254 }

255 return ret;

256 }

257

258 static int GCC_FMT_ATTR(4, 5)

259 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp,

260 const char *fmt, ...)

261 {

262 int ret;

263 va_list va;

264

265 va_start(va, fmt);

266 ret = nbd_opt_vdrop(client, type, errp, fmt, va);

267 va_end(va);

268

269 return ret;

270 }

271

272 static int GCC_FMT_ATTR(3, 4)

273 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...)

274 {

275 int ret;

276 va_list va;

277

278 va_start(va, fmt);

279 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va);

280 va_end(va);

281

282 return ret;

283 }

284

285 /* Read size bytes from the unparsed payload of the current option.

286 * Return -errno on I/O error, 0 if option was completely handled by

287 * sending a reply about inconsistent lengths, or 1 on success. */

288 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size,

289 Error **errp)

290 {

291 if (size > client->optlen) {

292 return nbd_opt_invalid(client, errp,

293 "Inconsistent lengths in option %s",

294 nbd_opt_lookup(client->opt));

295 }

296 client->optlen -= size;

297 return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1;

298 }

299

300 /* Drop size bytes from the unparsed payload of the current option.

301 * Return -errno on I/O error, 0 if option was completely handled by

302 * sending a reply about inconsistent lengths, or 1 on success. */

303 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp)

304 {

305 if (size > client->optlen) {

306 return nbd_opt_invalid(client, errp,

307 "Inconsistent lengths in option %s",

308 nbd_opt_lookup(client->opt));

309 }

310 client->optlen -= size;

311 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1;

312 }

313

314 /* nbd_opt_read_name

315 *

316 * Read a string with the format:

317 * uint32_t len (<= NBD_MAX_NAME_SIZE)

318 * len bytes string (not 0-terminated)

319 *

320 * @name should be enough to store NBD_MAX_NAME_SIZE+1.

321 * If @length is non-null, it will be set to the actual string length.

322 *

323 * Return -errno on I/O error, 0 if option was completely handled by

324 * sending a reply about inconsistent lengths, or 1 on success.

325 */

326 static int nbd_opt_read_name(NBDClient *client, char *name, uint32_t *length,

327 Error **errp)

328 {

329 int ret;

330 uint32_t len;

331

332 ret = nbd_opt_read(client, &len, sizeof(len), errp);

333 if (ret <= 0) {

334 return ret;

335 }

336 len = cpu_to_be32(len);

337

338 if (len > NBD_MAX_NAME_SIZE) {

339 return nbd_opt_invalid(client, errp,

340 "Invalid name length: %" PRIu32, len);

341 }

342

343 ret = nbd_opt_read(client, name, len, errp);

344 if (ret <= 0) {

345 return ret;

346 }

347 name[len] = '\0';

348

349 if (length) {

350 *length = len;

351 }

352

353 return 1;

354 }

355

356 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.

357 * Return -errno on error, 0 on success. */

358 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp,

359 Error **errp)

360 {

361 size_t name_len, desc_len;

362 uint32_t len;

363 const char *name = exp->name ? exp->name : "";

364 const char *desc = exp->description ? exp->description : "";

365 QIOChannel *ioc = client->ioc;

366 int ret;

367

368 trace_nbd_negotiate_send_rep_list(name, desc);

369 name_len = strlen(name);

370 desc_len = strlen(desc);

371 len = name_len + desc_len + sizeof(len);

372 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp);

373 if (ret < 0) {

374 return ret;

375 }

376

377 len = cpu_to_be32(name_len);

378 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {

379 error_prepend(errp, "write failed (name length): ");

380 return -EINVAL;

381 }

382

383 if (nbd_write(ioc, name, name_len, errp) < 0) {

384 error_prepend(errp, "write failed (name buffer): ");

385 return -EINVAL;

386 }

387

388 if (nbd_write(ioc, desc, desc_len, errp) < 0) {

389 error_prepend(errp, "write failed (description buffer): ");

390 return -EINVAL;

391 }

392

393 return 0;

394 }

395

396 /* Process the NBD_OPT_LIST command, with a potential series of replies.

397 * Return -errno on error, 0 on success. */

398 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)

399 {

400 NBDExport *exp;

401 assert(client->opt == NBD_OPT_LIST);

402

403 /* For each export, send a NBD_REP_SERVER reply. */

404 QTAILQ_FOREACH(exp, &exports, next) {

405 if (nbd_negotiate_send_rep_list(client, exp, errp)) {

406 return -EINVAL;

407 }

408 }

409 /* Finish with a NBD_REP_ACK. */

410 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);

411 }

412

413 static void nbd_check_meta_export(NBDClient *client)

414 {

415 client->export_meta.valid &= client->exp == client->export_meta.exp;

416 }

417

418 /* Send a reply to NBD_OPT_EXPORT_NAME.

419 * Return -errno on error, 0 on success. */

420 static int nbd_negotiate_handle_export_name(NBDClient *client,

421 uint16_t myflags, bool no_zeroes,

422 Error **errp)

423 {

424 char name[NBD_MAX_NAME_SIZE + 1];

425 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";

426 size_t len;

427 int ret;

428

429 /* Client sends:

430 [20 .. xx] export name (length bytes)

431 Server replies:

432 [ 0 .. 7] size

433 [ 8 .. 9] export flags

434 [10 .. 133] reserved (0) [unless no_zeroes]

435 */

436 trace_nbd_negotiate_handle_export_name();

437 if (client->optlen >= sizeof(name)) {

438 error_setg(errp, "Bad length received");

439 return -EINVAL;

440 }

441 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) {

442 return -EIO;

443 }

444 name[client->optlen] = '\0';

445 client->optlen = 0;

446

447 trace_nbd_negotiate_handle_export_name_request(name);

448

449 client->exp = nbd_export_find(name);

450 if (!client->exp) {

451 error_setg(errp, "export not found");

452 return -EINVAL;

453 }

454

455 trace_nbd_negotiate_new_style_size_flags(client->exp->size,

456 client->exp->nbdflags | myflags);

457 stq_be_p(buf, client->exp->size);

458 stw_be_p(buf + 8, client->exp->nbdflags | myflags);

459 len = no_zeroes ? 10 : sizeof(buf);

460 ret = nbd_write(client->ioc, buf, len, errp);

461 if (ret < 0) {

462 error_prepend(errp, "write failed: ");

463 return ret;

464 }

465

466 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);

467 nbd_export_get(client->exp);

468 nbd_check_meta_export(client);

469

470 return 0;

471 }

472

473 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.

474 * The buffer does NOT include the info type prefix.

475 * Return -errno on error, 0 if ready to send more. */

476 static int nbd_negotiate_send_info(NBDClient *client,

477 uint16_t info, uint32_t length, void *buf,

478 Error **errp)

479 {

480 int rc;

481

482 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);

483 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO,

484 sizeof(info) + length, errp);

485 if (rc < 0) {

486 return rc;

487 }

488 info = cpu_to_be16(info);

489 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) {

490 return -EIO;

491 }

492 if (nbd_write(client->ioc, buf, length, errp) < 0) {

493 return -EIO;

494 }

495 return 0;

496 }

497

498 /* nbd_reject_length: Handle any unexpected payload.

499 * @fatal requests that we quit talking to the client, even if we are able

500 * to successfully send an error reply.

501 * Return:

502 * -errno transmission error occurred or @fatal was requested, errp is set

503 * 0 error message successfully sent to client, errp is not set

504 */

505 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp)

506 {

507 int ret;

508

509 assert(client->optlen);

510 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length",

511 nbd_opt_lookup(client->opt));

512 if (fatal && !ret) {

513 error_setg(errp, "option '%s' has unexpected length",

514 nbd_opt_lookup(client->opt));

515 return -EINVAL;

516 }

517 return ret;

518 }

519

520 /* Handle NBD_OPT_INFO and NBD_OPT_GO.

521 * Return -errno on error, 0 if ready for next option, and 1 to move

522 * into transmission phase. */

523 static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,

524 Error **errp)

525 {

526 int rc;

527 char name[NBD_MAX_NAME_SIZE + 1];

528 NBDExport *exp;

529 uint16_t requests;

530 uint16_t request;

531 uint32_t namelen;

532 bool sendname = false;

533 bool blocksize = false;

534 uint32_t sizes[3];

535 char buf[sizeof(uint64_t) + sizeof(uint16_t)];

536

537 /* Client sends:

538 4 bytes: L, name length (can be 0)

539 L bytes: export name

540 2 bytes: N, number of requests (can be 0)

541 N * 2 bytes: N requests

542 */

543 rc = nbd_opt_read_name(client, name, &namelen, errp);

544 if (rc <= 0) {

545 return rc;

546 }

547 trace_nbd_negotiate_handle_export_name_request(name);

548

549 rc = nbd_opt_read(client, &requests, sizeof(requests), errp);

550 if (rc <= 0) {

551 return rc;

552 }

553 requests = be16_to_cpu(requests);

554 trace_nbd_negotiate_handle_info_requests(requests);

555 while (requests--) {

556 rc = nbd_opt_read(client, &request, sizeof(request), errp);

557 if (rc <= 0) {

558 return rc;

559 }

560 request = be16_to_cpu(request);

561 trace_nbd_negotiate_handle_info_request(request,

562 nbd_info_lookup(request));

563 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;

564 * everything else is either a request we don't know or

565 * something we send regardless of request */

566 switch (request) {

567 case NBD_INFO_NAME:

568 sendname = true;

569 break;

570 case NBD_INFO_BLOCK_SIZE:

571 blocksize = true;

572 break;

573 }

574 }

575 if (client->optlen) {

576 return nbd_reject_length(client, false, errp);

577 }

578

579 exp = nbd_export_find(name);

580 if (!exp) {

581 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN,

582 errp, "export '%s' not present",

583 name);

584 }

585

586 /* Don't bother sending NBD_INFO_NAME unless client requested it */

587 if (sendname) {

588 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name,

589 errp);

590 if (rc < 0) {

591 return rc;

592 }

593 }

594

595 /* Send NBD_INFO_DESCRIPTION only if available, regardless of

596 * client request */

597 if (exp->description) {

598 size_t len = strlen(exp->description);

599

600 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION,

601 len, exp->description, errp);

602 if (rc < 0) {

603 return rc;

604 }

605 }

606

607 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size

608 * according to whether the client requested it, and according to

609 * whether this is OPT_INFO or OPT_GO. */

610 /* minimum - 1 for back-compat, or 512 if client is new enough.

611 * TODO: consult blk_bs(blk)->bl.request_alignment? */

612 sizes[0] =

613 (client->opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1;

614 /* preferred - Hard-code to 4096 for now.

615 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */

616 sizes[1] = 4096;

617 /* maximum - At most 32M, but smaller as appropriate. */

618 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE);

619 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]);

620 sizes[0] = cpu_to_be32(sizes[0]);

621 sizes[1] = cpu_to_be32(sizes[1]);

622 sizes[2] = cpu_to_be32(sizes[2]);

623 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE,

624 sizeof(sizes), sizes, errp);

625 if (rc < 0) {

626 return rc;

627 }

628

629 /* Send NBD_INFO_EXPORT always */

630 trace_nbd_negotiate_new_style_size_flags(exp->size,

631 exp->nbdflags | myflags);

632 stq_be_p(buf, exp->size);

633 stw_be_p(buf + 8, exp->nbdflags | myflags);

634 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT,

635 sizeof(buf), buf, errp);

636 if (rc < 0) {

637 return rc;

638 }

639

640 /* If the client is just asking for NBD_OPT_INFO, but forgot to

641 * request block sizes, return an error.

642 * TODO: consult blk_bs(blk)->request_align, and only error if it

643 * is not 1? */

644 if (client->opt == NBD_OPT_INFO && !blocksize) {

645 return nbd_negotiate_send_rep_err(client,

646 NBD_REP_ERR_BLOCK_SIZE_REQD,

647 errp,

648 "request NBD_INFO_BLOCK_SIZE to "

649 "use this export");

650 }

651

652 /* Final reply */

653 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);

654 if (rc < 0) {

655 return rc;

656 }

657

658 if (client->opt == NBD_OPT_GO) {

659 client->exp = exp;

660 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);

661 nbd_export_get(client->exp);

662 nbd_check_meta_export(client);

663 rc = 1;

664 }

665 return rc;

666 }

667

668

669 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the

670 * new channel for all further (now-encrypted) communication. */

671 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,

672 Error **errp)

673 {

674 QIOChannel *ioc;

675 QIOChannelTLS *tioc;

676 struct NBDTLSHandshakeData data = { 0 };

677

678 assert(client->opt == NBD_OPT_STARTTLS);

679

680 trace_nbd_negotiate_handle_starttls();

681 ioc = client->ioc;

682

683 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) {

684 return NULL;

685 }

686

687 tioc = qio_channel_tls_new_server(ioc,

688 client->tlscreds,

689 client->tlsauthz,

690 errp);

691 if (!tioc) {

692 return NULL;

693 }

694

695 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");

696 trace_nbd_negotiate_handle_starttls_handshake();

697 data.loop = g_main_loop_new(g_main_context_default(), FALSE);

698 qio_channel_tls_handshake(tioc,

699 nbd_tls_handshake,

700 &data,

701 NULL,

702 NULL);

703

704 if (!data.complete) {

705 g_main_loop_run(data.loop);

706 }

707 g_main_loop_unref(data.loop);

708 if (data.error) {

709 object_unref(OBJECT(tioc));

710 error_propagate(errp, data.error);

711 return NULL;

712 }

713

714 return QIO_CHANNEL(tioc);

715 }

716

717 /* nbd_negotiate_send_meta_context

718 *

719 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT

720 *

721 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead.

722 */

723 static int nbd_negotiate_send_meta_context(NBDClient *client,

724 const char *context,

725 uint32_t context_id,

726 Error **errp)

727 {

728 NBDOptionReplyMetaContext opt;

729 struct iovec iov[] = {

730 {.iov_base = &opt, .iov_len = sizeof(opt)},

731 {.iov_base = (void *)context, .iov_len = strlen(context)}

732 };

733

734 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {

735 context_id = 0;

736 }

737

738 trace_nbd_negotiate_meta_query_reply(context, context_id);

739 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT,

740 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len);

741 stl_be_p(&opt.context_id, context_id);

742

743 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0;

744 }

745

746 /* Read strlen(@pattern) bytes, and set @match to true if they match @pattern.

747 * @match is never set to false.

748 *

749 * Return -errno on I/O error, 0 if option was completely handled by

750 * sending a reply about inconsistent lengths, or 1 on success.

751 *

752 * Note: return code = 1 doesn't mean that we've read exactly @pattern.

753 * It only means that there are no errors.

754 */

755 static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match,

756 Error **errp)

757 {

758 int ret;

759 char *query;

760 size_t len = strlen(pattern);

761

762 assert(len);

763

764 query = g_malloc(len);

765 ret = nbd_opt_read(client, query, len, errp);

766 if (ret <= 0) {

767 g_free(query);

768 return ret;

769 }

770

771 if (strncmp(query, pattern, len) == 0) {

772 trace_nbd_negotiate_meta_query_parse(pattern);

773 *match = true;

774 } else {

775 trace_nbd_negotiate_meta_query_skip("pattern not matched");

776 }

777 g_free(query);

778

779 return 1;

780 }

781

782 /*

783 * Read @len bytes, and set @match to true if they match @pattern, or if @len

784 * is 0 and the client is performing _LIST_. @match is never set to false.

785 *

786 * Return -errno on I/O error, 0 if option was completely handled by

787 * sending a reply about inconsistent lengths, or 1 on success.

788 *

789 * Note: return code = 1 doesn't mean that we've read exactly @pattern.

790 * It only means that there are no errors.

791 */

792 static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,

793 uint32_t len, bool *match, Error **errp)

794 {

795 if (len == 0) {

796 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {

797 *match = true;

798 }

799 trace_nbd_negotiate_meta_query_parse("empty");

800 return 1;

801 }

802

803 if (len != strlen(pattern)) {

804 trace_nbd_negotiate_meta_query_skip("different lengths");

805 return nbd_opt_skip(client, len, errp);

806 }

807

808 return nbd_meta_pattern(client, pattern, match, errp);

809 }

810

811 /* nbd_meta_base_query

812 *

813 * Handle queries to 'base' namespace. For now, only the base:allocation

814 * context is available. 'len' is the amount of text remaining to be read from

815 * the current name, after the 'base:' portion has been stripped.

816 *

817 * Return -errno on I/O error, 0 if option was completely handled by

818 * sending a reply about inconsistent lengths, or 1 on success.

819 */

820 static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,

821 uint32_t len, Error **errp)

822 {

823 return nbd_meta_empty_or_pattern(client, "allocation", len,

824 &meta->base_allocation, errp);

825 }

826

827 /* nbd_meta_bitmap_query

828 *

829 * Handle query to 'qemu:' namespace.

830 * @len is the amount of text remaining to be read from the current name, after

831 * the 'qemu:' portion has been stripped.

832 *

833 * Return -errno on I/O error, 0 if option was completely handled by

834 * sending a reply about inconsistent lengths, or 1 on success. */

835 static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta,

836 uint32_t len, Error **errp)

837 {

838 bool dirty_bitmap = false;

839 size_t dirty_bitmap_len = strlen("dirty-bitmap:");

840 int ret;

841

842 if (!meta->exp->export_bitmap) {

843 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported");

844 return nbd_opt_skip(client, len, errp);

845 }

846

847 if (len == 0) {

848 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {

849 meta->bitmap = true;

850 }

851 trace_nbd_negotiate_meta_query_parse("empty");

852 return 1;

853 }

854

855 if (len < dirty_bitmap_len) {

856 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");

857 return nbd_opt_skip(client, len, errp);

858 }

859

860 len -= dirty_bitmap_len;

861 ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp);

862 if (ret <= 0) {

863 return ret;

864 }

865 if (!dirty_bitmap) {

866 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");

867 return nbd_opt_skip(client, len, errp);

868 }

869

870 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:");

871

872 return nbd_meta_empty_or_pattern(

873 client, meta->exp->export_bitmap_context +

874 strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp);

875 }

876

877 /* nbd_negotiate_meta_query

878 *

879 * Parse namespace name and call corresponding function to parse body of the

880 * query.

881 *

882 * The only supported namespace now is 'base'.

883 *

884 * The function aims not wasting time and memory to read long unknown namespace

885 * names.

886 *

887 * Return -errno on I/O error, 0 if option was completely handled by

888 * sending a reply about inconsistent lengths, or 1 on success. */

889 static int nbd_negotiate_meta_query(NBDClient *client,

890 NBDExportMetaContexts *meta, Error **errp)

891 {

892 /*

893 * Both 'qemu' and 'base' namespaces have length = 5 including a

894 * colon. If another length namespace is later introduced, this

895 * should certainly be refactored.

896 */

897 int ret;

898 size_t ns_len = 5;

899 char ns[5];

900 uint32_t len;

901

902 ret = nbd_opt_read(client, &len, sizeof(len), errp);

903 if (ret <= 0) {

904 return ret;

905 }

906 len = cpu_to_be32(len);

907

908 if (len < ns_len) {

909 trace_nbd_negotiate_meta_query_skip("length too short");

910 return nbd_opt_skip(client, len, errp);

911 }

912

913 len -= ns_len;

914 ret = nbd_opt_read(client, ns, ns_len, errp);

915 if (ret <= 0) {

916 return ret;

917 }

918

919 if (!strncmp(ns, "base:", ns_len)) {

920 trace_nbd_negotiate_meta_query_parse("base:");

921 return nbd_meta_base_query(client, meta, len, errp);

922 } else if (!strncmp(ns, "qemu:", ns_len)) {

923 trace_nbd_negotiate_meta_query_parse("qemu:");

924 return nbd_meta_qemu_query(client, meta, len, errp);

925 }

926

927 trace_nbd_negotiate_meta_query_skip("unknown namespace");

928 return nbd_opt_skip(client, len, errp);

929 }

930

931 /* nbd_negotiate_meta_queries

932 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT

933 *

934 * Return -errno on I/O error, or 0 if option was completely handled. */

935 static int nbd_negotiate_meta_queries(NBDClient *client,

936 NBDExportMetaContexts *meta, Error **errp)

937 {

938 int ret;

939 char export_name[NBD_MAX_NAME_SIZE + 1];

940 NBDExportMetaContexts local_meta;

941 uint32_t nb_queries;

942 int i;

943

944 if (!client->structured_reply) {

945 return nbd_opt_invalid(client, errp,

946 "request option '%s' when structured reply "

947 "is not negotiated",

948 nbd_opt_lookup(client->opt));

949 }

950

951 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {

952 /* Only change the caller's meta on SET. */

953 meta = &local_meta;

954 }

955

956 memset(meta, 0, sizeof(*meta));

957

958 ret = nbd_opt_read_name(client, export_name, NULL, errp);

959 if (ret <= 0) {

960 return ret;

961 }

962

963 meta->exp = nbd_export_find(export_name);

964 if (meta->exp == NULL) {

965 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp,

966 "export '%s' not present", export_name);

967 }

968

969 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp);

970 if (ret <= 0) {

971 return ret;

972 }

973 nb_queries = cpu_to_be32(nb_queries);

974 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt),

975 export_name, nb_queries);

976

977 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) {

978 /* enable all known contexts */

979 meta->base_allocation = true;

980 meta->bitmap = !!meta->exp->export_bitmap;

981 } else {

982 for (i = 0; i < nb_queries; ++i) {

983 ret = nbd_negotiate_meta_query(client, meta, errp);

984 if (ret <= 0) {

985 return ret;

986 }

987 }

988 }

989

990 if (meta->base_allocation) {

991 ret = nbd_negotiate_send_meta_context(client, "base:allocation",

992 NBD_META_ID_BASE_ALLOCATION,

993 errp);

994 if (ret < 0) {

995 return ret;

996 }

997 }

998

999 if (meta->bitmap) {

1000 ret = nbd_negotiate_send_meta_context(client,

1001 meta->exp->export_bitmap_context,

1002 NBD_META_ID_DIRTY_BITMAP,

1003 errp);

1004 if (ret < 0) {

1005 return ret;

1006 }

1007 }

1008

1009 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);

1010 if (ret == 0) {

1011 meta->valid = true;

1012 }

1013

1014 return ret;

1015 }

1016

1017 /* nbd_negotiate_options

1018 * Process all NBD_OPT_* client option commands, during fixed newstyle

1019 * negotiation.

1020 * Return:

1021 * -errno on error, errp is set

1022 * 0 on successful negotiation, errp is not set

1023 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,

1024 * errp is not set

1025 */

1026 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,

1027 Error **errp)

1028 {

1029 uint32_t flags;

1030 bool fixedNewstyle = false;

1031 bool no_zeroes = false;

1032

1033 /* Client sends:

1034 [ 0 .. 3] client flags

1035

1036 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO:

1037 [ 0 .. 7] NBD_OPTS_MAGIC

1038 [ 8 .. 11] NBD option

1039 [12 .. 15] Data length

1040 ... Rest of request

1041

1042 [ 0 .. 7] NBD_OPTS_MAGIC

1043 [ 8 .. 11] Second NBD option

1044 [12 .. 15] Data length

1045 ... Rest of request

1046 */

1047

1048 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) {

1049 return -EIO;

1050 }

1051 trace_nbd_negotiate_options_flags(flags);

1052 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {

1053 fixedNewstyle = true;

1054 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;

1055 }

1056 if (flags & NBD_FLAG_C_NO_ZEROES) {

1057 no_zeroes = true;

1058 flags &= ~NBD_FLAG_C_NO_ZEROES;

1059 }

1060 if (flags != 0) {

1061 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);

1062 return -EINVAL;

1063 }

1064

1065 while (1) {

1066 int ret;

1067 uint32_t option, length;

1068 uint64_t magic;

1069

1070 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) {

1071 return -EINVAL;

1072 }

1073 trace_nbd_negotiate_options_check_magic(magic);

1074 if (magic != NBD_OPTS_MAGIC) {

1075 error_setg(errp, "Bad magic received");

1076 return -EINVAL;

1077 }

1078

1079 if (nbd_read32(client->ioc, &option, "option", errp) < 0) {

1080 return -EINVAL;

1081 }

1082 client->opt = option;

1083

1084 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) {

1085 return -EINVAL;

1086 }

1087 assert(!client->optlen);

1088 client->optlen = length;

1089

1090 if (length > NBD_MAX_BUFFER_SIZE) {

1091 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",

1092 length, NBD_MAX_BUFFER_SIZE);

1093 return -EINVAL;

1094 }

1095

1096 trace_nbd_negotiate_options_check_option(option,

1097 nbd_opt_lookup(option));

1098 if (client->tlscreds &&

1099 client->ioc == (QIOChannel *)client->sioc) {

1100 QIOChannel *tioc;

1101 if (!fixedNewstyle) {

1102 error_setg(errp, "Unsupported option 0x%" PRIx32, option);

1103 return -EINVAL;

1104 }

1105 switch (option) {

1106 case NBD_OPT_STARTTLS:

1107 if (length) {

1108 /* Unconditionally drop the connection if the client

1109 * can't start a TLS negotiation correctly */

1110 return nbd_reject_length(client, true, errp);

1111 }

1112 tioc = nbd_negotiate_handle_starttls(client, errp);

1113 if (!tioc) {

1114 return -EIO;

1115 }

1116 ret = 0;

1117 object_unref(OBJECT(client->ioc));

1118 client->ioc = QIO_CHANNEL(tioc);

1119 break;

1120

1121 case NBD_OPT_EXPORT_NAME:

1122 /* No way to return an error to client, so drop connection */

1123 error_setg(errp, "Option 0x%x not permitted before TLS",

1124 option);

1125 return -EINVAL;

1126

1127 default:

1128 /* Let the client keep trying, unless they asked to

1129 * quit. Always try to give an error back to the

1130 * client; but when replying to OPT_ABORT, be aware

1131 * that the client may hang up before receiving the

1132 * error, in which case we are fine ignoring the

1133 * resulting EPIPE. */

1134 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD,

1135 option == NBD_OPT_ABORT ? NULL : errp,

1136 "Option 0x%" PRIx32

1137 " not permitted before TLS", option);

1138 if (option == NBD_OPT_ABORT) {

1139 return 1;

1140 }

1141 break;

1142 }

1143 } else if (fixedNewstyle) {

1144 switch (option) {

1145 case NBD_OPT_LIST:

1146 if (length) {

1147 ret = nbd_reject_length(client, false, errp);

1148 } else {

1149 ret = nbd_negotiate_handle_list(client, errp);

1150 }

1151 break;

1152

1153 case NBD_OPT_ABORT:

1154 /* NBD spec says we must try to reply before

1155 * disconnecting, but that we must also tolerate

1156 * guests that don't wait for our reply. */

1157 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL);

1158 return 1;

1159

1160 case NBD_OPT_EXPORT_NAME:

1161 return nbd_negotiate_handle_export_name(client,

1162 myflags, no_zeroes,

1163 errp);

1164

1165 case NBD_OPT_INFO:

1166 case NBD_OPT_GO:

1167 ret = nbd_negotiate_handle_info(client, myflags, errp);

1168 if (ret == 1) {

1169 assert(option == NBD_OPT_GO);

1170 return 0;

1171 }

1172 break;

1173

1174 case NBD_OPT_STARTTLS:

1175 if (length) {

1176 ret = nbd_reject_length(client, false, errp);

1177 } else if (client->tlscreds) {

1178 ret = nbd_negotiate_send_rep_err(client,

1179 NBD_REP_ERR_INVALID, errp,

1180 "TLS already enabled");

1181 } else {

1182 ret = nbd_negotiate_send_rep_err(client,

1183 NBD_REP_ERR_POLICY, errp,

1184 "TLS not configured");

1185 }

1186 break;

1187

1188 case NBD_OPT_STRUCTURED_REPLY:

1189 if (length) {

1190 ret = nbd_reject_length(client, false, errp);

1191 } else if (client->structured_reply) {

1192 ret = nbd_negotiate_send_rep_err(

1193 client, NBD_REP_ERR_INVALID, errp,

1194 "structured reply already negotiated");

1195 } else {

1196 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);

1197 client->structured_reply = true;

1198 myflags |= NBD_FLAG_SEND_DF;

1199 }

1200 break;

1201

1202 case NBD_OPT_LIST_META_CONTEXT:

1203 case NBD_OPT_SET_META_CONTEXT:

1204 ret = nbd_negotiate_meta_queries(client, &client->export_meta,

1205 errp);

1206 break;

1207

1208 default:

1209 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp,

1210 "Unsupported option %" PRIu32 " (%s)",

1211 option, nbd_opt_lookup(option));

1212 break;

1213 }

1214 } else {

1215 /*

1216 * If broken new-style we should drop the connection

1217 * for anything except NBD_OPT_EXPORT_NAME

1218 */

1219 switch (option) {

1220 case NBD_OPT_EXPORT_NAME:

1221 return nbd_negotiate_handle_export_name(client,

1222 myflags, no_zeroes,

1223 errp);

1224

1225 default:

1226 error_setg(errp, "Unsupported option %" PRIu32 " (%s)",

1227 option, nbd_opt_lookup(option));

1228 return -EINVAL;

1229 }

1230 }

1231 if (ret < 0) {

1232 return ret;

1233 }

1234 }

1235 }

1236

1237 /* nbd_negotiate

1238 * Return:

1239 * -errno on error, errp is set

1240 * 0 on successful negotiation, errp is not set

1241 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,

1242 * errp is not set

1243 */

1244 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)

1245 {

1246 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";

1247 int ret;

1248 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |

1249 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA |

1250 NBD_FLAG_SEND_WRITE_ZEROES | NBD_FLAG_SEND_CACHE);

1251

1252 /* Old style negotiation header, no room for options

1253 [ 0 .. 7] passwd ("NBDMAGIC")

1254 [ 8 .. 15] magic (NBD_CLIENT_MAGIC)

1255 [16 .. 23] size

1256 [24 .. 27] export flags (zero-extended)

1257 [28 .. 151] reserved (0)

1258

1259 New style negotiation header, client can send options

1260 [ 0 .. 7] passwd ("NBDMAGIC")

1261 [ 8 .. 15] magic (NBD_OPTS_MAGIC)

1262 [16 .. 17] server flags (0)

1263 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO....

1264 */

1265

1266 qio_channel_set_blocking(client->ioc, false, NULL);

1267

1268 trace_nbd_negotiate_begin();

1269 memcpy(buf, "NBDMAGIC", 8);

1270

1271 stq_be_p(buf + 8, NBD_OPTS_MAGIC);

1272 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);

1273

1274 if (nbd_write(client->ioc, buf, 18, errp) < 0) {

1275 error_prepend(errp, "write failed: ");

1276 return -EINVAL;

1277 }

1278 ret = nbd_negotiate_options(client, myflags, errp);

1279 if (ret != 0) {

1280 if (ret < 0) {

1281 error_prepend(errp, "option negotiation failed: ");

1282 }

1283 return ret;

1284 }

1285

1286 assert(!client->optlen);

1287 trace_nbd_negotiate_success();

1288

1289 return 0;

1290 }

1291

1292 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request,

1293 Error **errp)

1294 {

1295 uint8_t buf[NBD_REQUEST_SIZE];

1296 uint32_t magic;

1297 int ret;

1298

1299 ret = nbd_read(ioc, buf, sizeof(buf), "request", errp);

1300 if (ret < 0) {

1301 return ret;

1302 }

1303

1304 /* Request

1305 [ 0 .. 3] magic (NBD_REQUEST_MAGIC)

1306 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...)

1307 [ 6 .. 7] type (NBD_CMD_READ, ...)

1308 [ 8 .. 15] handle

1309 [16 .. 23] from

1310 [24 .. 27] len

1311 */

1312

1313 magic = ldl_be_p(buf);

1314 request->flags = lduw_be_p(buf + 4);

1315 request->type = lduw_be_p(buf + 6);

1316 request->handle = ldq_be_p(buf + 8);

1317 request->from = ldq_be_p(buf + 16);

1318 request->len = ldl_be_p(buf + 24);

1319

1320 trace_nbd_receive_request(magic, request->flags, request->type,

1321 request->from, request->len);

1322

1323 if (magic != NBD_REQUEST_MAGIC) {

1324 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic);

1325 return -EINVAL;

1326 }

1327 return 0;

1328 }

1329

1330 #define MAX_NBD_REQUESTS 16

1331

1332 void nbd_client_get(NBDClient *client)

1333 {

1334 client->refcount++;

1335 }

1336

1337 void nbd_client_put(NBDClient *client)

1338 {

1339 if (--client->refcount == 0) {

1340 /* The last reference should be dropped by client->close,

1341 * which is called by client_close.

1342 */

1343 assert(client->closing);

1344

1345 qio_channel_detach_aio_context(client->ioc);

1346 object_unref(OBJECT(client->sioc));

1347 object_unref(OBJECT(client->ioc));

1348 if (client->tlscreds) {

1349 object_unref(OBJECT(client->tlscreds));

1350 }

1351 g_free(client->tlsauthz);

1352 if (client->exp) {

1353 QTAILQ_REMOVE(&client->exp->clients, client, next);

1354 nbd_export_put(client->exp);

1355 }

1356 g_free(client);

1357 }

1358 }

1359

1360 static void client_close(NBDClient *client, bool negotiated)

1361 {

1362 if (client->closing) {

1363 return;

1364 }

1365

1366 client->closing = true;

1367

1368 /* Force requests to finish. They will drop their own references,

1369 * then we'll close the socket and free the NBDClient.

1370 */

1371 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,

1372 NULL);

1373

1374 /* Also tell the client, so that they release their reference. */

1375 if (client->close_fn) {

1376 client->close_fn(client, negotiated);

1377 }

1378 }

1379

1380 static NBDRequestData *nbd_request_get(NBDClient *client)

1381 {

1382 NBDRequestData *req;

1383

1384 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);

1385 client->nb_requests++;

1386

1387 req = g_new0(NBDRequestData, 1);

1388 nbd_client_get(client);

1389 req->client = client;

1390 return req;

1391 }

1392

1393 static void nbd_request_put(NBDRequestData *req)

1394 {

1395 NBDClient *client = req->client;

1396

1397 if (req->data) {

1398 qemu_vfree(req->data);

1399 }

1400 g_free(req);

1401

1402 client->nb_requests--;

1403 nbd_client_receive_next_request(client);

1404

1405 nbd_client_put(client);

1406 }

1407

1408 static void blk_aio_attached(AioContext *ctx, void *opaque)

1409 {

1410 NBDExport *exp = opaque;

1411 NBDClient *client;

1412

1413 trace_nbd_blk_aio_attached(exp->name, ctx);

1414

1415 exp->ctx = ctx;

1416

1417 QTAILQ_FOREACH(client, &exp->clients, next) {

1418 qio_channel_attach_aio_context(client->ioc, ctx);

1419 if (client->recv_coroutine) {

1420 aio_co_schedule(ctx, client->recv_coroutine);

1421 }

1422 if (client->send_coroutine) {

1423 aio_co_schedule(ctx, client->send_coroutine);

1424 }

1425 }

1426 }

1427

1428 static void blk_aio_detach(void *opaque)

1429 {

1430 NBDExport *exp = opaque;

1431 NBDClient *client;

1432

1433 trace_nbd_blk_aio_detach(exp->name, exp->ctx);

1434

1435 QTAILQ_FOREACH(client, &exp->clients, next) {

1436 qio_channel_detach_aio_context(client->ioc);

1437 }

1438

1439 exp->ctx = NULL;

1440 }

1441

1442 static void nbd_eject_notifier(Notifier *n, void *data)

1443 {

1444 NBDExport *exp = container_of(n, NBDExport, eject_notifier);

1445 nbd_export_close(exp);

1446 }

1447

1448 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,

1449 uint64_t size, const char *name, const char *desc,

1450 const char *bitmap, uint16_t nbdflags,

1451 void (*close)(NBDExport *), bool writethrough,

1452 BlockBackend *on_eject_blk, Error **errp)

1453 {

1454 AioContext *ctx;

1455 BlockBackend *blk;

1456 NBDExport *exp = g_new0(NBDExport, 1);

1457 uint64_t perm;

1458 int ret;

1459

1460 /*

1461 * NBD exports are used for non-shared storage migration. Make sure

1462 * that BDRV_O_INACTIVE is cleared and the image is ready for write

1463 * access since the export could be available before migration handover.

1464 */

1465 assert(name);

1466 ctx = bdrv_get_aio_context(bs);

1467 aio_context_acquire(ctx);

1468 bdrv_invalidate_cache(bs, NULL);

1469 aio_context_release(ctx);

1470

1471 /* Don't allow resize while the NBD server is running, otherwise we don't

1472 * care what happens with the node. */

1473 perm = BLK_PERM_CONSISTENT_READ;

1474 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) {

1475 perm |= BLK_PERM_WRITE;

1476 }

1477 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |

1478 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD);

1479 ret = blk_insert_bs(blk, bs, errp);

1480 if (ret < 0) {

1481 goto fail;

1482 }

1483 blk_set_enable_write_cache(blk, !writethrough);

1484

1485 exp->refcount = 1;

1486 QTAILQ_INIT(&exp->clients);

1487 exp->blk = blk;

1488 assert(dev_offset <= INT64_MAX);

1489 exp->dev_offset = dev_offset;

1490 exp->name = g_strdup(name);

1491 exp->description = g_strdup(desc);

1492 exp->nbdflags = nbdflags;

1493 assert(size <= INT64_MAX - dev_offset);

1494 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE);

1495

1496 if (bitmap) {

1497 BdrvDirtyBitmap *bm = NULL;

1498

1499 while (true) {

1500 bm = bdrv_find_dirty_bitmap(bs, bitmap);

1501 if (bm != NULL || bs->backing == NULL) {

1502 break;

1503 }

1504

1505 bs = bs->backing->bs;

1506 }

1507

1508 if (bm == NULL) {

1509 error_setg(errp, "Bitmap '%s' is not found", bitmap);

1510 goto fail;

1511 }

1512

1513 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) {

1514 goto fail;

1515 }

1516

1517 if ((nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) &&

1518 bdrv_dirty_bitmap_enabled(bm)) {

1519 error_setg(errp,

1520 "Enabled bitmap '%s' incompatible with readonly export",

1521 bitmap);

1522 goto fail;

1523 }

1524

1525 bdrv_dirty_bitmap_set_busy(bm, true);

1526 exp->export_bitmap = bm;

1527 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s",

1528 bitmap);

1529 }

1530

1531 exp->close = close;

1532 exp->ctx = blk_get_aio_context(blk);

1533 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);

1534

1535 if (on_eject_blk) {

1536 blk_ref(on_eject_blk);

1537 exp->eject_notifier_blk = on_eject_blk;

1538 exp->eject_notifier.notify = nbd_eject_notifier;

1539 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);

1540 }

1541 QTAILQ_INSERT_TAIL(&exports, exp, next);

1542 nbd_export_get(exp);

1543 return exp;

1544

1545 fail:

1546 blk_unref(blk);

1547 g_free(exp->name);

1548 g_free(exp->description);

1549 g_free(exp);

1550 return NULL;

1551 }

1552

1553 NBDExport *nbd_export_find(const char *name)

1554 {

1555 NBDExport *exp;

1556 QTAILQ_FOREACH(exp, &exports, next) {

1557 if (strcmp(name, exp->name) == 0) {

1558 return exp;

1559 }

1560 }

1561

1562 return NULL;

1563 }

1564

1565 void nbd_export_close(NBDExport *exp)

1566 {

1567 NBDClient *client, *next;

1568

1569 nbd_export_get(exp);

1570 /*

1571 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a

1572 * close mode that stops advertising the export to new clients but

1573 * still permits existing clients to run to completion? Because of

1574 * that possibility, nbd_export_close() can be called more than

1575 * once on an export.

1576 */

1577 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {

1578 client_close(client, true);

1579 }

1580 if (exp->name) {

1581 nbd_export_put(exp);

1582 g_free(exp->name);

1583 exp->name = NULL;

1584 QTAILQ_REMOVE(&exports, exp, next);

1585 }

1586 g_free(exp->description);

1587 exp->description = NULL;

1588 nbd_export_put(exp);

1589 }

1590

1591 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp)

1592 {

1593 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) {

1594 nbd_export_close(exp);

1595 return;

1596 }

1597

1598 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE);

1599

1600 error_setg(errp, "export '%s' still in use", exp->name);

1601 error_append_hint(errp, "Use mode='hard' to force client disconnect\n");

1602 }

1603

1604 void nbd_export_get(NBDExport *exp)

1605 {

1606 assert(exp->refcount > 0);

1607 exp->refcount++;

1608 }

1609

1610 void nbd_export_put(NBDExport *exp)

1611 {

1612 assert(exp->refcount > 0);

1613 if (exp->refcount == 1) {

1614 nbd_export_close(exp);

1615 }

1616

1617 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen

1618 * if someone calls nbd_export_put() on named export not through

1619 * nbd_export_set_name() when refcount is 1. So, let's assert that

1620 * it is > 0.

1621 */

1622 assert(exp->refcount > 0);

1623 if (--exp->refcount == 0) {

1624 assert(exp->name == NULL);

1625 assert(exp->description == NULL);

1626

1627 if (exp->close) {

1628 exp->close(exp);

1629 }

1630

1631 if (exp->blk) {

1632 if (exp->eject_notifier_blk) {

1633 notifier_remove(&exp->eject_notifier);

1634 blk_unref(exp->eject_notifier_blk);

1635 }

1636 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,

1637 blk_aio_detach, exp);

1638 blk_unref(exp->blk);

1639 exp->blk = NULL;

1640 }

1641

1642 if (exp->export_bitmap) {

1643 bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false);

1644 g_free(exp->export_bitmap_context);

1645 }

1646

1647 g_free(exp);

1648 }

1649 }

1650

1651 BlockBackend *nbd_export_get_blockdev(NBDExport *exp)

1652 {

1653 return exp->blk;

1654 }

1655

1656 void nbd_export_close_all(void)

1657 {

1658 NBDExport *exp, *next;

1659

1660 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {

1661 nbd_export_close(exp);

1662 }

1663 }

1664

1665 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov,

1666 unsigned niov, Error **errp)

1667 {

1668 int ret;

1669

1670 g_assert(qemu_in_coroutine());

1671 qemu_co_mutex_lock(&client->send_lock);

1672 client->send_coroutine = qemu_coroutine_self();

1673

1674 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0;

1675

1676 client->send_coroutine = NULL;

1677 qemu_co_mutex_unlock(&client->send_lock);

1678

1679 return ret;

1680 }

1681

1682 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,

1683 uint64_t handle)

1684 {

1685 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);

1686 stl_be_p(&reply->error, error);

1687 stq_be_p(&reply->handle, handle);

1688 }

1689

1690 static int nbd_co_send_simple_reply(NBDClient *client,

1691 uint64_t handle,

1692 uint32_t error,

1693 void *data,

1694 size_t len,

1695 Error **errp)

1696 {

1697 NBDSimpleReply reply;

1698 int nbd_err = system_errno_to_nbd_errno(error);

1699 struct iovec iov[] = {

1700 {.iov_base = &reply, .iov_len = sizeof(reply)},

1701 {.iov_base = data, .iov_len = len}

1702 };

1703

1704 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err),

1705 len);

1706 set_be_simple_reply(&reply, nbd_err, handle);

1707

1708 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp);

1709 }

1710

1711 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags,

1712 uint16_t type, uint64_t handle, uint32_t length)

1713 {

1714 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC);

1715 stw_be_p(&chunk->flags, flags);

1716 stw_be_p(&chunk->type, type);

1717 stq_be_p(&chunk->handle, handle);

1718 stl_be_p(&chunk->length, length);

1719 }

1720

1721 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client,

1722 uint64_t handle,

1723 Error **errp)

1724 {

1725 NBDStructuredReplyChunk chunk;

1726 struct iovec iov[] = {

1727 {.iov_base = &chunk, .iov_len = sizeof(chunk)},

1728 };

1729

1730 trace_nbd_co_send_structured_done(handle);

1731 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0);

1732

1733 return nbd_co_send_iov(client, iov, 1, errp);

1734 }

1735

1736 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client,

1737 uint64_t handle,

1738 uint64_t offset,

1739 void *data,

1740 size_t size,

1741 bool final,

1742 Error **errp)

1743 {

1744 NBDStructuredReadData chunk;

1745 struct iovec iov[] = {

1746 {.iov_base = &chunk, .iov_len = sizeof(chunk)},

1747 {.iov_base = data, .iov_len = size}

1748 };

1749

1750 assert(size);

1751 trace_nbd_co_send_structured_read(handle, offset, data, size);

1752 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,

1753 NBD_REPLY_TYPE_OFFSET_DATA, handle,

1754 sizeof(chunk) - sizeof(chunk.h) + size);

1755 stq_be_p(&chunk.offset, offset);

1756

1757 return nbd_co_send_iov(client, iov, 2, errp);

1758 }

1759

1760 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client,

1761 uint64_t handle,

1762 uint32_t error,

1763 const char *msg,

1764 Error **errp)

1765 {

1766 NBDStructuredError chunk;

1767 int nbd_err = system_errno_to_nbd_errno(error);

1768 struct iovec iov[] = {

1769 {.iov_base = &chunk, .iov_len = sizeof(chunk)},

1770 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0},

1771 };

1772

1773 assert(nbd_err);

1774 trace_nbd_co_send_structured_error(handle, nbd_err,

1775 nbd_err_lookup(nbd_err), msg ? msg : "");

1776 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle,

1777 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);

1778 stl_be_p(&chunk.error, nbd_err);

1779 stw_be_p(&chunk.message_length, iov[1].iov_len);

1780

1781 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp);

1782 }

1783

1784 /* Do a sparse read and send the structured reply to the client.

1785 * Returns -errno if sending fails. bdrv_block_status_above() failure is

1786 * reported to the client, at which point this function succeeds.

1787 */

1788 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,

1789 uint64_t handle,

1790 uint64_t offset,

1791 uint8_t *data,

1792 size_t size,

1793 Error **errp)

1794 {

1795 int ret = 0;

1796 NBDExport *exp = client->exp;

1797 size_t progress = 0;

1798

1799 while (progress < size) {

1800 int64_t pnum;

1801 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL,

1802 offset + progress,

1803 size - progress, &pnum, NULL,

1804 NULL);

1805 bool final;

1806

1807 if (status < 0) {

1808 char *msg = g_strdup_printf("unable to check for holes: %s",

1809 strerror(-status));

1810

1811 ret = nbd_co_send_structured_error(client, handle, -status, msg,

1812 errp);

1813 g_free(msg);

1814 return ret;

1815 }

1816 assert(pnum && pnum <= size - progress);

1817 final = progress + pnum == size;

1818 if (status & BDRV_BLOCK_ZERO) {

1819 NBDStructuredReadHole chunk;

1820 struct iovec iov[] = {

1821 {.iov_base = &chunk, .iov_len = sizeof(chunk)},

1822 };

1823

1824 trace_nbd_co_send_structured_read_hole(handle, offset + progress,

1825 pnum);

1826 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,

1827 NBD_REPLY_TYPE_OFFSET_HOLE,

1828 handle, sizeof(chunk) - sizeof(chunk.h));

1829 stq_be_p(&chunk.offset, offset + progress);

1830 stl_be_p(&chunk.length, pnum);

1831 ret = nbd_co_send_iov(client, iov, 1, errp);

1832 } else {

1833 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset,

1834 data + progress, pnum);

1835 if (ret < 0) {

1836 error_setg_errno(errp, -ret, "reading from file failed");

1837 break;

1838 }

1839 ret = nbd_co_send_structured_read(client, handle, offset + progress,

1840 data + progress, pnum, final,

1841 errp);

1842 }

1843

1844 if (ret < 0) {

1845 break;

1846 }

1847 progress += pnum;

1848 }

1849 return ret;

1850 }

1851

1852 /*

1853 * Populate @extents from block status. Update @bytes to be the actual

1854 * length encoded (which may be smaller than the original), and update

1855 * @nb_extents to the number of extents used.

1856 *

1857 * Returns zero on success and -errno on bdrv_block_status_above failure.

1858 */

1859 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset,

1860 uint64_t *bytes, NBDExtent *extents,

1861 unsigned int *nb_extents)

1862 {

1863 uint64_t remaining_bytes = *bytes;

1864 NBDExtent *extent = extents, *extents_end = extents + *nb_extents;

1865 bool first_extent = true;

1866

1867 assert(*nb_extents);

1868 while (remaining_bytes) {

1869 uint32_t flags;

1870 int64_t num;

1871 int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes,

1872 &num, NULL, NULL);

1873

1874 if (ret < 0) {

1875 return ret;

1876 }

1877

1878 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) |

1879 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0);

1880 offset += num;

1881 remaining_bytes -= num;

1882

1883 if (first_extent) {

1884 extent->flags = flags;

1885 extent->length = num;

1886 first_extent = false;

1887 continue;

1888 }

1889

1890 if (flags == extent->flags) {

1891 /* extend current extent */

1892 extent->length += num;

1893 } else {

1894 if (extent + 1 == extents_end) {

1895 break;

1896 }

1897

1898 /* start new extent */

1899 extent++;

1900 extent->flags = flags;

1901 extent->length = num;

1902 }

1903 }

1904

1905 extents_end = extent + 1;

1906

1907 for (extent = extents; extent < extents_end; extent++) {

1908 extent->flags = cpu_to_be32(extent->flags);

1909 extent->length = cpu_to_be32(extent->length);

1910 }

1911

1912 *bytes -= remaining_bytes;

1913 *nb_extents = extents_end - extents;

1914

1915 return 0;

1916 }

1917

1918 /* nbd_co_send_extents

1919 *

1920 * @length is only for tracing purposes (and may be smaller or larger

1921 * than the client's original request). @last controls whether

1922 * NBD_REPLY_FLAG_DONE is sent. @extents should already be in

1923 * big-endian format.

1924 */

1925 static int nbd_co_send_extents(NBDClient *client, uint64_t handle,

1926 NBDExtent *extents, unsigned int nb_extents,

1927 uint64_t length, bool last,

1928 uint32_t context_id, Error **errp)

1929 {

1930 NBDStructuredMeta chunk;

1931

1932 struct iovec iov[] = {

1933 {.iov_base = &chunk, .iov_len = sizeof(chunk)},

1934 {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])}

1935 };

1936

1937 trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last);

1938 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0,

1939 NBD_REPLY_TYPE_BLOCK_STATUS,

1940 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);

1941 stl_be_p(&chunk.context_id, context_id);

1942

1943 return nbd_co_send_iov(client, iov, 2, errp);

1944 }

1945

1946 /* Get block status from the exported device and send it to the client */

1947 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle,

1948 BlockDriverState *bs, uint64_t offset,

1949 uint32_t length, bool dont_fragment,

1950 bool last, uint32_t context_id,

1951 Error **errp)

1952 {

1953 int ret;

1954 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS;

1955 NBDExtent *extents = g_new(NBDExtent, nb_extents);

1956 uint64_t final_length = length;

1957

1958 ret = blockstatus_to_extents(bs, offset, &final_length, extents,

1959 &nb_extents);

1960 if (ret < 0) {

1961 g_free(extents);

1962 return nbd_co_send_structured_error(

1963 client, handle, -ret, "can't get block status", errp);

1964 }

1965

1966 ret = nbd_co_send_extents(client, handle, extents, nb_extents,

1967 final_length, last, context_id, errp);

1968

1969 g_free(extents);

1970

1971 return ret;

1972 }

1973

1974 /*

1975 * Populate @extents from a dirty bitmap. Unless @dont_fragment, the

1976 * final extent may exceed the original @length. Store in @length the

1977 * byte length encoded (which may be smaller or larger than the

1978 * original), and return the number of extents used.

1979 */

1980 static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset,

1981 uint64_t *length, NBDExtent *extents,

1982 unsigned int nb_extents,

1983 bool dont_fragment)

1984 {

1985 uint64_t begin = offset, end = offset;

1986 uint64_t overall_end = offset + *length;

1987 unsigned int i = 0;

1988 BdrvDirtyBitmapIter *it;

1989 bool dirty;

1990

1991 bdrv_dirty_bitmap_lock(bitmap);

1992

1993 it = bdrv_dirty_iter_new(bitmap);

1994 dirty = bdrv_get_dirty_locked(NULL, bitmap, offset);

1995

1996 assert(begin < overall_end && nb_extents);

1997 while (begin < overall_end && i < nb_extents) {

1998 bool next_dirty = !dirty;

1999

2000 if (dirty) {

2001 end = bdrv_dirty_bitmap_next_zero(bitmap, begin, UINT64_MAX);

2002 } else {

2003 bdrv_set_dirty_iter(it, begin);

2004 end = bdrv_dirty_iter_next(it);

2005 }

2006 if (end == -1 || end - begin > UINT32_MAX) {

2007 /* Cap to an aligned value < 4G beyond begin. */

2008 end = MIN(bdrv_dirty_bitmap_size(bitmap),

2009 begin + UINT32_MAX + 1 -

2010 bdrv_dirty_bitmap_granularity(bitmap));

2011 next_dirty = dirty;

2012 }

2013 if (dont_fragment && end > overall_end) {

2014 end = overall_end;

2015 }

2016

2017 extents[i].length = cpu_to_be32(end - begin);

2018 extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0);

2019 i++;

2020 begin = end;

2021 dirty = next_dirty;

2022 }

2023

2024 bdrv_dirty_iter_free(it);

2025

2026 bdrv_dirty_bitmap_unlock(bitmap);

2027

2028 assert(offset < end);

2029 *length = end - offset;

2030 return i;

2031 }

2032

2033 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle,

2034 BdrvDirtyBitmap *bitmap, uint64_t offset,

2035 uint32_t length, bool dont_fragment, bool last,

2036 uint32_t context_id, Error **errp)

2037 {

2038 int ret;

2039 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS;

2040 NBDExtent *extents = g_new(NBDExtent, nb_extents);

2041 uint64_t final_length = length;

2042

2043 nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents,

2044 nb_extents, dont_fragment);

2045

2046 ret = nbd_co_send_extents(client, handle, extents, nb_extents,

2047 final_length, last, context_id, errp);

2048

2049 g_free(extents);

2050

2051 return ret;

2052 }

2053

2054 /* nbd_co_receive_request

2055 * Collect a client request. Return 0 if request looks valid, -EIO to drop

2056 * connection right away, and any other negative value to report an error to

2057 * the client (although the caller may still need to disconnect after reporting

2058 * the error).

2059 */

2060 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,

2061 Error **errp)

2062 {

2063 NBDClient *client = req->client;

2064 int valid_flags;

2065

2066 g_assert(qemu_in_coroutine());

2067 assert(client->recv_coroutine == qemu_coroutine_self());

2068 if (nbd_receive_request(client->ioc, request, errp) < 0) {

2069 return -EIO;

2070 }

2071

2072 trace_nbd_co_receive_request_decode_type(request->handle, request->type,

2073 nbd_cmd_lookup(request->type));

2074

2075 if (request->type != NBD_CMD_WRITE) {

2076 /* No payload, we are ready to read the next request. */

2077 req->complete = true;

2078 }

2079

2080 if (request->type == NBD_CMD_DISC) {

2081 /* Special case: we're going to disconnect without a reply,

2082 * whether or not flags, from, or len are bogus */

2083 return -EIO;

2084 }

2085

2086 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE ||

2087 request->type == NBD_CMD_CACHE)

2088 {

2089 if (request->len > NBD_MAX_BUFFER_SIZE) {

2090 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",

2091 request->len, NBD_MAX_BUFFER_SIZE);

2092 return -EINVAL;

2093 }

2094

2095 req->data = blk_try_blockalign(client->exp->blk, request->len);

2096 if (req->data == NULL) {

2097 error_setg(errp, "No memory");

2098 return -ENOMEM;

2099 }

2100 }

2101 if (request->type == NBD_CMD_WRITE) {

2102 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data",

2103 errp) < 0)

2104 {

2105 return -EIO;

2106 }

2107 req->complete = true;

2108

2109 trace_nbd_co_receive_request_payload_received(request->handle,

2110 request->len);

2111 }

2112

2113 /* Sanity checks. */

2114 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY &&

2115 (request->type == NBD_CMD_WRITE ||

2116 request->type == NBD_CMD_WRITE_ZEROES ||

2117 request->type == NBD_CMD_TRIM)) {

2118 error_setg(errp, "Export is read-only");

2119 return -EROFS;

2120 }

2121 if (request->from > client->exp->size ||

2122 request->len > client->exp->size - request->from) {

2123 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32

2124 ", Size: %" PRIu64, request->from, request->len,

2125 client->exp->size);

2126 return (request->type == NBD_CMD_WRITE ||

2127 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL;

2128 }

2129 valid_flags = NBD_CMD_FLAG_FUA;

2130 if (request->type == NBD_CMD_READ && client->structured_reply) {

2131 valid_flags |= NBD_CMD_FLAG_DF;

2132 } else if (request->type == NBD_CMD_WRITE_ZEROES) {

2133 valid_flags |= NBD_CMD_FLAG_NO_HOLE;

2134 } else if (request->type == NBD_CMD_BLOCK_STATUS) {

2135 valid_flags |= NBD_CMD_FLAG_REQ_ONE;

2136 }

2137 if (request->flags & ~valid_flags) {

2138 error_setg(errp, "unsupported flags for command %s (got 0x%x)",

2139 nbd_cmd_lookup(request->type), request->flags);

2140 return -EINVAL;

2141 }

2142

2143 return 0;

2144 }

2145

2146 /* Send simple reply without a payload, or a structured error

2147 * @error_msg is ignored if @ret >= 0

2148 * Returns 0 if connection is still live, -errno on failure to talk to client

2149 */

2150 static coroutine_fn int nbd_send_generic_reply(NBDClient *client,

2151 uint64_t handle,

2152 int ret,

2153 const char *error_msg,

2154 Error **errp)

2155 {

2156 if (client->structured_reply && ret < 0) {

2157 return nbd_co_send_structured_error(client, handle, -ret, error_msg,

2158 errp);

2159 } else {

2160 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0,

2161 NULL, 0, errp);

2162 }

2163 }

2164

2165 /* Handle NBD_CMD_READ request.

2166 * Return -errno if sending fails. Other errors are reported directly to the

2167 * client as an error reply. */

2168 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request,

2169 uint8_t *data, Error **errp)

2170 {

2171 int ret;

2172 NBDExport *exp = client->exp;

2173

2174 assert(request->type == NBD_CMD_READ || request->type == NBD_CMD_CACHE);

2175

2176 /* XXX: NBD Protocol only documents use of FUA with WRITE */

2177 if (request->flags & NBD_CMD_FLAG_FUA) {

2178 ret = blk_co_flush(exp->blk);

2179 if (ret < 0) {

2180 return nbd_send_generic_reply(client, request->handle, ret,

2181 "flush failed", errp);

2182 }

2183 }

2184

2185 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) &&

2186 request->len && request->type != NBD_CMD_CACHE)

2187 {

2188 return nbd_co_send_sparse_read(client, request->handle, request->from,

2189 data, request->len, errp);

2190 }

2191

2192 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data,

2193 request->len);

2194 if (ret < 0 || request->type == NBD_CMD_CACHE) {

2195 return nbd_send_generic_reply(client, request->handle, ret,

2196 "reading from file failed", errp);

2197 }

2198

2199 if (client->structured_reply) {

2200 if (request->len) {

2201 return nbd_co_send_structured_read(client, request->handle,

2202 request->from, data,

2203 request->len, true, errp);

2204 } else {

2205 return nbd_co_send_structured_done(client, request->handle, errp);

2206 }

2207 } else {

2208 return nbd_co_send_simple_reply(client, request->handle, 0,

2209 data, request->len, errp);

2210 }

2211 }

2212

2213 /* Handle NBD request.

2214 * Return -errno if sending fails. Other errors are reported directly to the

2215 * client as an error reply. */

2216 static coroutine_fn int nbd_handle_request(NBDClient *client,

2217 NBDRequest *request,

2218 uint8_t *data, Error **errp)

2219 {

2220 int ret;

2221 int flags;

2222 NBDExport *exp = client->exp;

2223 char *msg;

2224

2225 switch (request->type) {

2226 case NBD_CMD_READ:

2227 case NBD_CMD_CACHE:

2228 return nbd_do_cmd_read(client, request, data, errp);

2229

2230 case NBD_CMD_WRITE:

2231 flags = 0;

2232 if (request->flags & NBD_CMD_FLAG_FUA) {

2233 flags |= BDRV_REQ_FUA;

2234 }

2235 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset,

2236 data, request->len, flags);

2237 return nbd_send_generic_reply(client, request->handle, ret,

2238 "writing to file failed", errp);

2239

2240 case NBD_CMD_WRITE_ZEROES:

2241 flags = 0;

2242 if (request->flags & NBD_CMD_FLAG_FUA) {

2243 flags |= BDRV_REQ_FUA;

2244 }

2245 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) {

2246 flags |= BDRV_REQ_MAY_UNMAP;

2247 }

2248 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset,

2249 request->len, flags);

2250 return nbd_send_generic_reply(client, request->handle, ret,

2251 "writing to file failed", errp);

2252

2253 case NBD_CMD_DISC:

2254 /* unreachable, thanks to special case in nbd_co_receive_request() */

2255 abort();

2256

2257 case NBD_CMD_FLUSH:

2258 ret = blk_co_flush(exp->blk);

2259 return nbd_send_generic_reply(client, request->handle, ret,

2260 "flush failed", errp);

2261

2262 case NBD_CMD_TRIM:

2263 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset,

2264 request->len);

2265 if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) {

2266 ret = blk_co_flush(exp->blk);

2267 }

2268 return nbd_send_generic_reply(client, request->handle, ret,

2269 "discard failed", errp);

2270

2271 case NBD_CMD_BLOCK_STATUS:

2272 if (!request->len) {

2273 return nbd_send_generic_reply(client, request->handle, -EINVAL,

2274 "need non-zero length", errp);

2275 }

2276 if (client->export_meta.valid &&

2277 (client->export_meta.base_allocation ||

2278 client->export_meta.bitmap))

2279 {

2280 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE;

2281

2282 if (client->export_meta.base_allocation) {

2283 ret = nbd_co_send_block_status(client, request->handle,

2284 blk_bs(exp->blk), request->from,

2285 request->len, dont_fragment,

2286 !client->export_meta.bitmap,

2287 NBD_META_ID_BASE_ALLOCATION,

2288 errp);

2289 if (ret < 0) {

2290 return ret;

2291 }

2292 }

2293

2294 if (client->export_meta.bitmap) {

2295 ret = nbd_co_send_bitmap(client, request->handle,

2296 client->exp->export_bitmap,

2297 request->from, request->len,

2298 dont_fragment,

2299 true, NBD_META_ID_DIRTY_BITMAP, errp);

2300 if (ret < 0) {

2301 return ret;

2302 }

2303 }

2304

2305 return ret;

2306 } else {

2307 return nbd_send_generic_reply(client, request->handle, -EINVAL,

2308 "CMD_BLOCK_STATUS not negotiated",

2309 errp);

2310 }

2311

2312 default:

2313 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received",

2314 request->type);

2315 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg,

2316 errp);

2317 g_free(msg);

2318 return ret;

2319 }

2320 }

2321

2322 /* Owns a reference to the NBDClient passed as opaque. */

2323 static coroutine_fn void nbd_trip(void *opaque)

2324 {

2325 NBDClient *client = opaque;

2326 NBDRequestData *req;

2327 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */

2328 int ret;

2329 Error *local_err = NULL;

2330

2331 trace_nbd_trip();

2332 if (client->closing) {

2333 nbd_client_put(client);

2334 return;

2335 }

2336

2337 req = nbd_request_get(client);

2338 ret = nbd_co_receive_request(req, &request, &local_err);

2339 client->recv_coroutine = NULL;

2340

2341 if (client->closing) {

2342 /*

2343 * The client may be closed when we are blocked in

2344 * nbd_co_receive_request()

2345 */

2346 goto done;

2347 }

2348

2349 nbd_client_receive_next_request(client);

2350 if (ret == -EIO) {

2351 goto disconnect;

2352 }

2353

2354 if (ret < 0) {

2355 /* It wans't -EIO, so, according to nbd_co_receive_request()

2356 * semantics, we should return the error to the client. */

2357 Error *export_err = local_err;

2358

2359 local_err = NULL;

2360 ret = nbd_send_generic_reply(client, request.handle, -EINVAL,

2361 error_get_pretty(export_err), &local_err);

2362 error_free(export_err);

2363 } else {

2364 ret = nbd_handle_request(client, &request, req->data, &local_err);

2365 }

2366 if (ret < 0) {

2367 error_prepend(&local_err, "Failed to send reply: ");

2368 goto disconnect;

2369 }

2370

2371 /* We must disconnect after NBD_CMD_WRITE if we did not

2372 * read the payload.

2373 */

2374 if (!req->complete) {

2375 error_setg(&local_err, "Request handling failed in intermediate state");

2376 goto disconnect;

2377 }

2378

2379 done:

2380 nbd_request_put(req);

2381 nbd_client_put(client);

2382 return;

2383

2384 disconnect:

2385 if (local_err) {

2386 error_reportf_err(local_err, "Disconnect client, due to: ");

2387 }

2388 nbd_request_put(req);

2389 client_close(client, true);

2390 nbd_client_put(client);

2391 }

2392

2393 static void nbd_client_receive_next_request(NBDClient *client)

2394 {

2395 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) {

2396 nbd_client_get(client);

2397 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);

2398 aio_co_schedule(client->exp->ctx, client->recv_coroutine);

2399 }

2400 }

2401

2402 static coroutine_fn void nbd_co_client_start(void *opaque)

2403 {

2404 NBDClient *client = opaque;

2405 Error *local_err = NULL;

2406

2407 qemu_co_mutex_init(&client->send_lock);

2408

2409 if (nbd_negotiate(client, &local_err)) {

2410 if (local_err) {

2411 error_report_err(local_err);

2412 }

2413 client_close(client, false);

2414 return;

2415 }

2416

2417 nbd_client_receive_next_request(client);

2418 }

2419

2420 /*

2421 * Create a new client listener using the given channel @sioc.

2422 * Begin servicing it in a coroutine. When the connection closes, call

2423 * @close_fn with an indication of whether the client completed negotiation.

2424 */

2425 void nbd_client_new(QIOChannelSocket *sioc,

2426 QCryptoTLSCreds *tlscreds,

2427 const char *tlsauthz,

2428 void (*close_fn)(NBDClient *, bool))

2429 {

2430 NBDClient *client;

2431 Coroutine *co;

2432

2433 client = g_new0(NBDClient, 1);

2434 client->refcount = 1;

2435 client->tlscreds = tlscreds;

2436 if (tlscreds) {

2437 object_ref(OBJECT(client->tlscreds));

2438 }

2439 client->tlsauthz = g_strdup(tlsauthz);

2440 client->sioc = sioc;

2441 object_ref(OBJECT(client->sioc));

2442 client->ioc = QIO_CHANNEL(sioc);

2443 object_ref(OBJECT(client->ioc));

2444 client->close_fn = close_fn;

2445

2446 co = qemu_coroutine_create(nbd_co_client_start, client);

2447 qemu_coroutine_enter(co);

2448 }