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Merge remote-tracking branch 'remotes/kraxel/tags/input-20171023-pull-request' into...
[qemu.git] / nbd / server.c
blob3df3548d6de45bfc728b58a11a12acfbdc6c4f71
1 /*
2 * Copyright (C) 2016-2017 Red Hat, Inc.
3 * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
4 *
5 * Network Block Device Server Side
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; under version 2 of the License.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
18 */
19
20 #include "qemu/osdep.h"
21 #include "qapi/error.h"
22 #include "trace.h"
23 #include "nbd-internal.h"
24
25 static int system_errno_to_nbd_errno(int err)
26 {
27 switch (err) {
28 case 0:
29 return NBD_SUCCESS;
30 case EPERM:
31 case EROFS:
32 return NBD_EPERM;
33 case EIO:
34 return NBD_EIO;
35 case ENOMEM:
36 return NBD_ENOMEM;
37 #ifdef EDQUOT
38 case EDQUOT:
39 #endif
40 case EFBIG:
41 case ENOSPC:
42 return NBD_ENOSPC;
43 case ESHUTDOWN:
44 return NBD_ESHUTDOWN;
45 case EINVAL:
46 default:
47 return NBD_EINVAL;
48 }
49 }
50
51 /* Definitions for opaque data types */
52
53 typedef struct NBDRequestData NBDRequestData;
54
55 struct NBDRequestData {
56 QSIMPLEQ_ENTRY(NBDRequestData) entry;
57 NBDClient *client;
58 uint8_t *data;
59 bool complete;
60 };
61
62 struct NBDExport {
63 int refcount;
64 void (*close)(NBDExport *exp);
65
66 BlockBackend *blk;
67 char *name;
68 char *description;
69 off_t dev_offset;
70 off_t size;
71 uint16_t nbdflags;
72 QTAILQ_HEAD(, NBDClient) clients;
73 QTAILQ_ENTRY(NBDExport) next;
74
75 AioContext *ctx;
76
77 BlockBackend *eject_notifier_blk;
78 Notifier eject_notifier;
79 };
80
81 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
82
83 struct NBDClient {
84 int refcount;
85 void (*close_fn)(NBDClient *client, bool negotiated);
86
87 NBDExport *exp;
88 QCryptoTLSCreds *tlscreds;
89 char *tlsaclname;
90 QIOChannelSocket *sioc; /* The underlying data channel */
91 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
92
93 Coroutine *recv_coroutine;
94
95 CoMutex send_lock;
96 Coroutine *send_coroutine;
97
98 QTAILQ_ENTRY(NBDClient) next;
99 int nb_requests;
100 bool closing;
101 };
102
103 /* That's all folks */
104
105 static void nbd_client_receive_next_request(NBDClient *client);
106
107 /* Basic flow for negotiation
108
109 Server Client
110 Negotiate
111
112 or
113
114 Server Client
115 Negotiate #1
116 Option
117 Negotiate #2
118
119 ----
120
121 followed by
122
123 Server Client
124 Request
125 Response
126 Request
127 Response
128 ...
129 ...
130 Request (type == 2)
131
132 */
133
134 /* Send a reply header, including length, but no payload.
135 * Return -errno on error, 0 on success. */
136 static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type,
137 uint32_t opt, uint32_t len, Error **errp)
138 {
139 uint64_t magic;
140
141 trace_nbd_negotiate_send_rep_len(opt, nbd_opt_lookup(opt),
142 type, nbd_rep_lookup(type), len);
143
144 assert(len < NBD_MAX_BUFFER_SIZE);
145 magic = cpu_to_be64(NBD_REP_MAGIC);
146 if (nbd_write(ioc, &magic, sizeof(magic), errp) < 0) {
147 error_prepend(errp, "write failed (rep magic): ");
148 return -EINVAL;
149 }
150
151 opt = cpu_to_be32(opt);
152 if (nbd_write(ioc, &opt, sizeof(opt), errp) < 0) {
153 error_prepend(errp, "write failed (rep opt): ");
154 return -EINVAL;
155 }
156
157 type = cpu_to_be32(type);
158 if (nbd_write(ioc, &type, sizeof(type), errp) < 0) {
159 error_prepend(errp, "write failed (rep type): ");
160 return -EINVAL;
161 }
162
163 len = cpu_to_be32(len);
164 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
165 error_prepend(errp, "write failed (rep data length): ");
166 return -EINVAL;
167 }
168 return 0;
169 }
170
171 /* Send a reply header with default 0 length.
172 * Return -errno on error, 0 on success. */
173 static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt,
174 Error **errp)
175 {
176 return nbd_negotiate_send_rep_len(ioc, type, opt, 0, errp);
177 }
178
179 /* Send an error reply.
180 * Return -errno on error, 0 on success. */
181 static int GCC_FMT_ATTR(5, 6)
182 nbd_negotiate_send_rep_err(QIOChannel *ioc, uint32_t type,
183 uint32_t opt, Error **errp, const char *fmt, ...)
184 {
185 va_list va;
186 char *msg;
187 int ret;
188 size_t len;
189
190 va_start(va, fmt);
191 msg = g_strdup_vprintf(fmt, va);
192 va_end(va);
193 len = strlen(msg);
194 assert(len < 4096);
195 trace_nbd_negotiate_send_rep_err(msg);
196 ret = nbd_negotiate_send_rep_len(ioc, type, opt, len, errp);
197 if (ret < 0) {
198 goto out;
199 }
200 if (nbd_write(ioc, msg, len, errp) < 0) {
201 error_prepend(errp, "write failed (error message): ");
202 ret = -EIO;
203 } else {
204 ret = 0;
205 }
206
207 out:
208 g_free(msg);
209 return ret;
210 }
211
212 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
213 * Return -errno on error, 0 on success. */
214 static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp,
215 Error **errp)
216 {
217 size_t name_len, desc_len;
218 uint32_t len;
219 const char *name = exp->name ? exp->name : "";
220 const char *desc = exp->description ? exp->description : "";
221 int ret;
222
223 trace_nbd_negotiate_send_rep_list(name, desc);
224 name_len = strlen(name);
225 desc_len = strlen(desc);
226 len = name_len + desc_len + sizeof(len);
227 ret = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, len,
228 errp);
229 if (ret < 0) {
230 return ret;
231 }
232
233 len = cpu_to_be32(name_len);
234 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
235 error_prepend(errp, "write failed (name length): ");
236 return -EINVAL;
237 }
238
239 if (nbd_write(ioc, name, name_len, errp) < 0) {
240 error_prepend(errp, "write failed (name buffer): ");
241 return -EINVAL;
242 }
243
244 if (nbd_write(ioc, desc, desc_len, errp) < 0) {
245 error_prepend(errp, "write failed (description buffer): ");
246 return -EINVAL;
247 }
248
249 return 0;
250 }
251
252 /* Process the NBD_OPT_LIST command, with a potential series of replies.
253 * Return -errno on error, 0 on success. */
254 static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length,
255 Error **errp)
256 {
257 NBDExport *exp;
258
259 if (length) {
260 if (nbd_drop(client->ioc, length, errp) < 0) {
261 return -EIO;
262 }
263 return nbd_negotiate_send_rep_err(client->ioc,
264 NBD_REP_ERR_INVALID, NBD_OPT_LIST,
265 errp,
266 "OPT_LIST should not have length");
267 }
268
269 /* For each export, send a NBD_REP_SERVER reply. */
270 QTAILQ_FOREACH(exp, &exports, next) {
271 if (nbd_negotiate_send_rep_list(client->ioc, exp, errp)) {
272 return -EINVAL;
273 }
274 }
275 /* Finish with a NBD_REP_ACK. */
276 return nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_LIST, errp);
277 }
278
279 /* Send a reply to NBD_OPT_EXPORT_NAME.
280 * Return -errno on error, 0 on success. */
281 static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length,
282 uint16_t myflags, bool no_zeroes,
283 Error **errp)
284 {
285 char name[NBD_MAX_NAME_SIZE + 1];
286 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
287 size_t len;
288 int ret;
289
290 /* Client sends:
291 [20 .. xx] export name (length bytes)
292 Server replies:
293 [ 0 .. 7] size
294 [ 8 .. 9] export flags
295 [10 .. 133] reserved (0) [unless no_zeroes]
296 */
297 trace_nbd_negotiate_handle_export_name();
298 if (length >= sizeof(name)) {
299 error_setg(errp, "Bad length received");
300 return -EINVAL;
301 }
302 if (nbd_read(client->ioc, name, length, errp) < 0) {
303 error_prepend(errp, "read failed: ");
304 return -EINVAL;
305 }
306 name[length] = '\0';
307
308 trace_nbd_negotiate_handle_export_name_request(name);
309
310 client->exp = nbd_export_find(name);
311 if (!client->exp) {
312 error_setg(errp, "export not found");
313 return -EINVAL;
314 }
315
316 trace_nbd_negotiate_new_style_size_flags(client->exp->size,
317 client->exp->nbdflags | myflags);
318 stq_be_p(buf, client->exp->size);
319 stw_be_p(buf + 8, client->exp->nbdflags | myflags);
320 len = no_zeroes ? 10 : sizeof(buf);
321 ret = nbd_write(client->ioc, buf, len, errp);
322 if (ret < 0) {
323 error_prepend(errp, "write failed: ");
324 return ret;
325 }
326
327 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
328 nbd_export_get(client->exp);
329
330 return 0;
331 }
332
333 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
334 * The buffer does NOT include the info type prefix.
335 * Return -errno on error, 0 if ready to send more. */
336 static int nbd_negotiate_send_info(NBDClient *client, uint32_t opt,
337 uint16_t info, uint32_t length, void *buf,
338 Error **errp)
339 {
340 int rc;
341
342 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);
343 rc = nbd_negotiate_send_rep_len(client->ioc, NBD_REP_INFO, opt,
344 sizeof(info) + length, errp);
345 if (rc < 0) {
346 return rc;
347 }
348 cpu_to_be16s(&info);
349 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) {
350 return -EIO;
351 }
352 if (nbd_write(client->ioc, buf, length, errp) < 0) {
353 return -EIO;
354 }
355 return 0;
356 }
357
358 /* Handle NBD_OPT_INFO and NBD_OPT_GO.
359 * Return -errno on error, 0 if ready for next option, and 1 to move
360 * into transmission phase. */
361 static int nbd_negotiate_handle_info(NBDClient *client, uint32_t length,
362 uint32_t opt, uint16_t myflags,
363 Error **errp)
364 {
365 int rc;
366 char name[NBD_MAX_NAME_SIZE + 1];
367 NBDExport *exp;
368 uint16_t requests;
369 uint16_t request;
370 uint32_t namelen;
371 bool sendname = false;
372 bool blocksize = false;
373 uint32_t sizes[3];
374 char buf[sizeof(uint64_t) + sizeof(uint16_t)];
375 const char *msg;
376
377 /* Client sends:
378 4 bytes: L, name length (can be 0)
379 L bytes: export name
380 2 bytes: N, number of requests (can be 0)
381 N * 2 bytes: N requests
382 */
383 if (length < sizeof(namelen) + sizeof(requests)) {
384 msg = "overall request too short";
385 goto invalid;
386 }
387 if (nbd_read(client->ioc, &namelen, sizeof(namelen), errp) < 0) {
388 return -EIO;
389 }
390 be32_to_cpus(&namelen);
391 length -= sizeof(namelen);
392 if (namelen > length - sizeof(requests) || (length - namelen) % 2) {
393 msg = "name length is incorrect";
394 goto invalid;
395 }
396 if (nbd_read(client->ioc, name, namelen, errp) < 0) {
397 return -EIO;
398 }
399 name[namelen] = '\0';
400 length -= namelen;
401 trace_nbd_negotiate_handle_export_name_request(name);
402
403 if (nbd_read(client->ioc, &requests, sizeof(requests), errp) < 0) {
404 return -EIO;
405 }
406 be16_to_cpus(&requests);
407 length -= sizeof(requests);
408 trace_nbd_negotiate_handle_info_requests(requests);
409 if (requests != length / sizeof(request)) {
410 msg = "incorrect number of requests for overall length";
411 goto invalid;
412 }
413 while (requests--) {
414 if (nbd_read(client->ioc, &request, sizeof(request), errp) < 0) {
415 return -EIO;
416 }
417 be16_to_cpus(&request);
418 length -= sizeof(request);
419 trace_nbd_negotiate_handle_info_request(request,
420 nbd_info_lookup(request));
421 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;
422 * everything else is either a request we don't know or
423 * something we send regardless of request */
424 switch (request) {
425 case NBD_INFO_NAME:
426 sendname = true;
427 break;
428 case NBD_INFO_BLOCK_SIZE:
429 blocksize = true;
430 break;
431 }
432 }
433
434 exp = nbd_export_find(name);
435 if (!exp) {
436 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_UNKNOWN,
437 opt, errp, "export '%s' not present",
438 name);
439 }
440
441 /* Don't bother sending NBD_INFO_NAME unless client requested it */
442 if (sendname) {
443 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_NAME, length, name,
444 errp);
445 if (rc < 0) {
446 return rc;
447 }
448 }
449
450 /* Send NBD_INFO_DESCRIPTION only if available, regardless of
451 * client request */
452 if (exp->description) {
453 size_t len = strlen(exp->description);
454
455 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_DESCRIPTION,
456 len, exp->description, errp);
457 if (rc < 0) {
458 return rc;
459 }
460 }
461
462 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size
463 * according to whether the client requested it, and according to
464 * whether this is OPT_INFO or OPT_GO. */
465 /* minimum - 1 for back-compat, or 512 if client is new enough.
466 * TODO: consult blk_bs(blk)->bl.request_alignment? */
467 sizes[0] = (opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1;
468 /* preferred - Hard-code to 4096 for now.
469 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */
470 sizes[1] = 4096;
471 /* maximum - At most 32M, but smaller as appropriate. */
472 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE);
473 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]);
474 cpu_to_be32s(&sizes[0]);
475 cpu_to_be32s(&sizes[1]);
476 cpu_to_be32s(&sizes[2]);
477 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_BLOCK_SIZE,
478 sizeof(sizes), sizes, errp);
479 if (rc < 0) {
480 return rc;
481 }
482
483 /* Send NBD_INFO_EXPORT always */
484 trace_nbd_negotiate_new_style_size_flags(exp->size,
485 exp->nbdflags | myflags);
486 stq_be_p(buf, exp->size);
487 stw_be_p(buf + 8, exp->nbdflags | myflags);
488 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_EXPORT,
489 sizeof(buf), buf, errp);
490 if (rc < 0) {
491 return rc;
492 }
493
494 /* If the client is just asking for NBD_OPT_INFO, but forgot to
495 * request block sizes, return an error.
496 * TODO: consult blk_bs(blk)->request_align, and only error if it
497 * is not 1? */
498 if (opt == NBD_OPT_INFO && !blocksize) {
499 return nbd_negotiate_send_rep_err(client->ioc,
500 NBD_REP_ERR_BLOCK_SIZE_REQD, opt,
501 errp,
502 "request NBD_INFO_BLOCK_SIZE to "
503 "use this export");
504 }
505
506 /* Final reply */
507 rc = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, opt, errp);
508 if (rc < 0) {
509 return rc;
510 }
511
512 if (opt == NBD_OPT_GO) {
513 client->exp = exp;
514 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
515 nbd_export_get(client->exp);
516 rc = 1;
517 }
518 return rc;
519
520 invalid:
521 if (nbd_drop(client->ioc, length, errp) < 0) {
522 return -EIO;
523 }
524 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, opt,
525 errp, "%s", msg);
526 }
527
528
529 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
530 * new channel for all further (now-encrypted) communication. */
531 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
532 uint32_t length,
533 Error **errp)
534 {
535 QIOChannel *ioc;
536 QIOChannelTLS *tioc;
537 struct NBDTLSHandshakeData data = { 0 };
538
539 trace_nbd_negotiate_handle_starttls();
540 ioc = client->ioc;
541 if (length) {
542 if (nbd_drop(ioc, length, errp) < 0) {
543 return NULL;
544 }
545 nbd_negotiate_send_rep_err(ioc, NBD_REP_ERR_INVALID, NBD_OPT_STARTTLS,
546 errp,
547 "OPT_STARTTLS should not have length");
548 return NULL;
549 }
550
551 if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK,
552 NBD_OPT_STARTTLS, errp) < 0) {
553 return NULL;
554 }
555
556 tioc = qio_channel_tls_new_server(ioc,
557 client->tlscreds,
558 client->tlsaclname,
559 errp);
560 if (!tioc) {
561 return NULL;
562 }
563
564 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
565 trace_nbd_negotiate_handle_starttls_handshake();
566 data.loop = g_main_loop_new(g_main_context_default(), FALSE);
567 qio_channel_tls_handshake(tioc,
568 nbd_tls_handshake,
569 &data,
570 NULL);
571
572 if (!data.complete) {
573 g_main_loop_run(data.loop);
574 }
575 g_main_loop_unref(data.loop);
576 if (data.error) {
577 object_unref(OBJECT(tioc));
578 error_propagate(errp, data.error);
579 return NULL;
580 }
581
582 return QIO_CHANNEL(tioc);
583 }
584
585 /* nbd_negotiate_options
586 * Process all NBD_OPT_* client option commands, during fixed newstyle
587 * negotiation.
588 * Return:
589 * -errno on error, errp is set
590 * 0 on successful negotiation, errp is not set
591 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
592 * errp is not set
593 */
594 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
595 Error **errp)
596 {
597 uint32_t flags;
598 bool fixedNewstyle = false;
599 bool no_zeroes = false;
600
601 /* Client sends:
602 [ 0 .. 3] client flags
603
604 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO:
605 [ 0 .. 7] NBD_OPTS_MAGIC
606 [ 8 .. 11] NBD option
607 [12 .. 15] Data length
608 ... Rest of request
609
610 [ 0 .. 7] NBD_OPTS_MAGIC
611 [ 8 .. 11] Second NBD option
612 [12 .. 15] Data length
613 ... Rest of request
614 */
615
616 if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) {
617 error_prepend(errp, "read failed: ");
618 return -EIO;
619 }
620 be32_to_cpus(&flags);
621 trace_nbd_negotiate_options_flags(flags);
622 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
623 fixedNewstyle = true;
624 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
625 }
626 if (flags & NBD_FLAG_C_NO_ZEROES) {
627 no_zeroes = true;
628 flags &= ~NBD_FLAG_C_NO_ZEROES;
629 }
630 if (flags != 0) {
631 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);
632 return -EINVAL;
633 }
634
635 while (1) {
636 int ret;
637 uint32_t option, length;
638 uint64_t magic;
639
640 if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) {
641 error_prepend(errp, "read failed: ");
642 return -EINVAL;
643 }
644 magic = be64_to_cpu(magic);
645 trace_nbd_negotiate_options_check_magic(magic);
646 if (magic != NBD_OPTS_MAGIC) {
647 error_setg(errp, "Bad magic received");
648 return -EINVAL;
649 }
650
651 if (nbd_read(client->ioc, &option,
652 sizeof(option), errp) < 0) {
653 error_prepend(errp, "read failed: ");
654 return -EINVAL;
655 }
656 option = be32_to_cpu(option);
657
658 if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) {
659 error_prepend(errp, "read failed: ");
660 return -EINVAL;
661 }
662 length = be32_to_cpu(length);
663
664 trace_nbd_negotiate_options_check_option(option,
665 nbd_opt_lookup(option));
666 if (client->tlscreds &&
667 client->ioc == (QIOChannel *)client->sioc) {
668 QIOChannel *tioc;
669 if (!fixedNewstyle) {
670 error_setg(errp, "Unsupported option 0x%" PRIx32, option);
671 return -EINVAL;
672 }
673 switch (option) {
674 case NBD_OPT_STARTTLS:
675 tioc = nbd_negotiate_handle_starttls(client, length, errp);
676 if (!tioc) {
677 return -EIO;
678 }
679 object_unref(OBJECT(client->ioc));
680 client->ioc = QIO_CHANNEL(tioc);
681 break;
682
683 case NBD_OPT_EXPORT_NAME:
684 /* No way to return an error to client, so drop connection */
685 error_setg(errp, "Option 0x%x not permitted before TLS",
686 option);
687 return -EINVAL;
688
689 default:
690 if (nbd_drop(client->ioc, length, errp) < 0) {
691 return -EIO;
692 }
693 ret = nbd_negotiate_send_rep_err(client->ioc,
694 NBD_REP_ERR_TLS_REQD,
695 option, errp,
696 "Option 0x%" PRIx32
697 "not permitted before TLS",
698 option);
699 if (ret < 0) {
700 return ret;
701 }
702 /* Let the client keep trying, unless they asked to
703 * quit. In this mode, we've already sent an error, so
704 * we can't ack the abort. */
705 if (option == NBD_OPT_ABORT) {
706 return 1;
707 }
708 break;
709 }
710 } else if (fixedNewstyle) {
711 switch (option) {
712 case NBD_OPT_LIST:
713 ret = nbd_negotiate_handle_list(client, length, errp);
714 if (ret < 0) {
715 return ret;
716 }
717 break;
718
719 case NBD_OPT_ABORT:
720 /* NBD spec says we must try to reply before
721 * disconnecting, but that we must also tolerate
722 * guests that don't wait for our reply. */
723 nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, option, NULL);
724 return 1;
725
726 case NBD_OPT_EXPORT_NAME:
727 return nbd_negotiate_handle_export_name(client, length,
728 myflags, no_zeroes,
729 errp);
730
731 case NBD_OPT_INFO:
732 case NBD_OPT_GO:
733 ret = nbd_negotiate_handle_info(client, length, option,
734 myflags, errp);
735 if (ret == 1) {
736 assert(option == NBD_OPT_GO);
737 return 0;
738 }
739 if (ret) {
740 return ret;
741 }
742 break;
743
744 case NBD_OPT_STARTTLS:
745 if (nbd_drop(client->ioc, length, errp) < 0) {
746 return -EIO;
747 }
748 if (client->tlscreds) {
749 ret = nbd_negotiate_send_rep_err(client->ioc,
750 NBD_REP_ERR_INVALID,
751 option, errp,
752 "TLS already enabled");
753 } else {
754 ret = nbd_negotiate_send_rep_err(client->ioc,
755 NBD_REP_ERR_POLICY,
756 option, errp,
757 "TLS not configured");
758 }
759 if (ret < 0) {
760 return ret;
761 }
762 break;
763 default:
764 if (nbd_drop(client->ioc, length, errp) < 0) {
765 return -EIO;
766 }
767 ret = nbd_negotiate_send_rep_err(client->ioc,
768 NBD_REP_ERR_UNSUP,
769 option, errp,
770 "Unsupported option 0x%"
771 PRIx32 " (%s)", option,
772 nbd_opt_lookup(option));
773 if (ret < 0) {
774 return ret;
775 }
776 break;
777 }
778 } else {
779 /*
780 * If broken new-style we should drop the connection
781 * for anything except NBD_OPT_EXPORT_NAME
782 */
783 switch (option) {
784 case NBD_OPT_EXPORT_NAME:
785 return nbd_negotiate_handle_export_name(client, length,
786 myflags, no_zeroes,
787 errp);
788
789 default:
790 error_setg(errp, "Unsupported option 0x%" PRIx32 " (%s)",
791 option, nbd_opt_lookup(option));
792 return -EINVAL;
793 }
794 }
795 }
796 }
797
798 /* nbd_negotiate
799 * Return:
800 * -errno on error, errp is set
801 * 0 on successful negotiation, errp is not set
802 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
803 * errp is not set
804 */
805 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
806 {
807 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";
808 int ret;
809 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
810 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA |
811 NBD_FLAG_SEND_WRITE_ZEROES);
812 bool oldStyle;
813
814 /* Old style negotiation header, no room for options
815 [ 0 .. 7] passwd ("NBDMAGIC")
816 [ 8 .. 15] magic (NBD_CLIENT_MAGIC)
817 [16 .. 23] size
818 [24 .. 27] export flags (zero-extended)
819 [28 .. 151] reserved (0)
820
821 New style negotiation header, client can send options
822 [ 0 .. 7] passwd ("NBDMAGIC")
823 [ 8 .. 15] magic (NBD_OPTS_MAGIC)
824 [16 .. 17] server flags (0)
825 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO....
826 */
827
828 qio_channel_set_blocking(client->ioc, false, NULL);
829
830 trace_nbd_negotiate_begin();
831 memcpy(buf, "NBDMAGIC", 8);
832
833 oldStyle = client->exp != NULL && !client->tlscreds;
834 if (oldStyle) {
835 trace_nbd_negotiate_old_style(client->exp->size,
836 client->exp->nbdflags | myflags);
837 stq_be_p(buf + 8, NBD_CLIENT_MAGIC);
838 stq_be_p(buf + 16, client->exp->size);
839 stl_be_p(buf + 24, client->exp->nbdflags | myflags);
840
841 if (nbd_write(client->ioc, buf, sizeof(buf), errp) < 0) {
842 error_prepend(errp, "write failed: ");
843 return -EINVAL;
844 }
845 } else {
846 stq_be_p(buf + 8, NBD_OPTS_MAGIC);
847 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);
848
849 if (nbd_write(client->ioc, buf, 18, errp) < 0) {
850 error_prepend(errp, "write failed: ");
851 return -EINVAL;
852 }
853 ret = nbd_negotiate_options(client, myflags, errp);
854 if (ret != 0) {
855 if (ret < 0) {
856 error_prepend(errp, "option negotiation failed: ");
857 }
858 return ret;
859 }
860 }
861
862 trace_nbd_negotiate_success();
863
864 return 0;
865 }
866
867 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request,
868 Error **errp)
869 {
870 uint8_t buf[NBD_REQUEST_SIZE];
871 uint32_t magic;
872 int ret;
873
874 ret = nbd_read(ioc, buf, sizeof(buf), errp);
875 if (ret < 0) {
876 return ret;
877 }
878
879 /* Request
880 [ 0 .. 3] magic (NBD_REQUEST_MAGIC)
881 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...)
882 [ 6 .. 7] type (NBD_CMD_READ, ...)
883 [ 8 .. 15] handle
884 [16 .. 23] from
885 [24 .. 27] len
886 */
887
888 magic = ldl_be_p(buf);
889 request->flags = lduw_be_p(buf + 4);
890 request->type = lduw_be_p(buf + 6);
891 request->handle = ldq_be_p(buf + 8);
892 request->from = ldq_be_p(buf + 16);
893 request->len = ldl_be_p(buf + 24);
894
895 trace_nbd_receive_request(magic, request->flags, request->type,
896 request->from, request->len);
897
898 if (magic != NBD_REQUEST_MAGIC) {
899 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic);
900 return -EINVAL;
901 }
902 return 0;
903 }
904
905 #define MAX_NBD_REQUESTS 16
906
907 void nbd_client_get(NBDClient *client)
908 {
909 client->refcount++;
910 }
911
912 void nbd_client_put(NBDClient *client)
913 {
914 if (--client->refcount == 0) {
915 /* The last reference should be dropped by client->close,
916 * which is called by client_close.
917 */
918 assert(client->closing);
919
920 qio_channel_detach_aio_context(client->ioc);
921 object_unref(OBJECT(client->sioc));
922 object_unref(OBJECT(client->ioc));
923 if (client->tlscreds) {
924 object_unref(OBJECT(client->tlscreds));
925 }
926 g_free(client->tlsaclname);
927 if (client->exp) {
928 QTAILQ_REMOVE(&client->exp->clients, client, next);
929 nbd_export_put(client->exp);
930 }
931 g_free(client);
932 }
933 }
934
935 static void client_close(NBDClient *client, bool negotiated)
936 {
937 if (client->closing) {
938 return;
939 }
940
941 client->closing = true;
942
943 /* Force requests to finish. They will drop their own references,
944 * then we'll close the socket and free the NBDClient.
945 */
946 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
947 NULL);
948
949 /* Also tell the client, so that they release their reference. */
950 if (client->close_fn) {
951 client->close_fn(client, negotiated);
952 }
953 }
954
955 static NBDRequestData *nbd_request_get(NBDClient *client)
956 {
957 NBDRequestData *req;
958
959 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
960 client->nb_requests++;
961
962 req = g_new0(NBDRequestData, 1);
963 nbd_client_get(client);
964 req->client = client;
965 return req;
966 }
967
968 static void nbd_request_put(NBDRequestData *req)
969 {
970 NBDClient *client = req->client;
971
972 if (req->data) {
973 qemu_vfree(req->data);
974 }
975 g_free(req);
976
977 client->nb_requests--;
978 nbd_client_receive_next_request(client);
979
980 nbd_client_put(client);
981 }
982
983 static void blk_aio_attached(AioContext *ctx, void *opaque)
984 {
985 NBDExport *exp = opaque;
986 NBDClient *client;
987
988 trace_nbd_blk_aio_attached(exp->name, ctx);
989
990 exp->ctx = ctx;
991
992 QTAILQ_FOREACH(client, &exp->clients, next) {
993 qio_channel_attach_aio_context(client->ioc, ctx);
994 if (client->recv_coroutine) {
995 aio_co_schedule(ctx, client->recv_coroutine);
996 }
997 if (client->send_coroutine) {
998 aio_co_schedule(ctx, client->send_coroutine);
999 }
1000 }
1001 }
1002
1003 static void blk_aio_detach(void *opaque)
1004 {
1005 NBDExport *exp = opaque;
1006 NBDClient *client;
1007
1008 trace_nbd_blk_aio_detach(exp->name, exp->ctx);
1009
1010 QTAILQ_FOREACH(client, &exp->clients, next) {
1011 qio_channel_detach_aio_context(client->ioc);
1012 }
1013
1014 exp->ctx = NULL;
1015 }
1016
1017 static void nbd_eject_notifier(Notifier *n, void *data)
1018 {
1019 NBDExport *exp = container_of(n, NBDExport, eject_notifier);
1020 nbd_export_close(exp);
1021 }
1022
1023 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
1024 uint16_t nbdflags, void (*close)(NBDExport *),
1025 bool writethrough, BlockBackend *on_eject_blk,
1026 Error **errp)
1027 {
1028 AioContext *ctx;
1029 BlockBackend *blk;
1030 NBDExport *exp = g_new0(NBDExport, 1);
1031 uint64_t perm;
1032 int ret;
1033
1034 /*
1035 * NBD exports are used for non-shared storage migration. Make sure
1036 * that BDRV_O_INACTIVE is cleared and the image is ready for write
1037 * access since the export could be available before migration handover.
1038 */
1039 ctx = bdrv_get_aio_context(bs);
1040 aio_context_acquire(ctx);
1041 bdrv_invalidate_cache(bs, NULL);
1042 aio_context_release(ctx);
1043
1044 /* Don't allow resize while the NBD server is running, otherwise we don't
1045 * care what happens with the node. */
1046 perm = BLK_PERM_CONSISTENT_READ;
1047 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) {
1048 perm |= BLK_PERM_WRITE;
1049 }
1050 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
1051 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD);
1052 ret = blk_insert_bs(blk, bs, errp);
1053 if (ret < 0) {
1054 goto fail;
1055 }
1056 blk_set_enable_write_cache(blk, !writethrough);
1057
1058 exp->refcount = 1;
1059 QTAILQ_INIT(&exp->clients);
1060 exp->blk = blk;
1061 exp->dev_offset = dev_offset;
1062 exp->nbdflags = nbdflags;
1063 exp->size = size < 0 ? blk_getlength(blk) : size;
1064 if (exp->size < 0) {
1065 error_setg_errno(errp, -exp->size,
1066 "Failed to determine the NBD export's length");
1067 goto fail;
1068 }
1069 exp->size -= exp->size % BDRV_SECTOR_SIZE;
1070
1071 exp->close = close;
1072 exp->ctx = blk_get_aio_context(blk);
1073 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
1074
1075 if (on_eject_blk) {
1076 blk_ref(on_eject_blk);
1077 exp->eject_notifier_blk = on_eject_blk;
1078 exp->eject_notifier.notify = nbd_eject_notifier;
1079 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
1080 }
1081 return exp;
1082
1083 fail:
1084 blk_unref(blk);
1085 g_free(exp);
1086 return NULL;
1087 }
1088
1089 NBDExport *nbd_export_find(const char *name)
1090 {
1091 NBDExport *exp;
1092 QTAILQ_FOREACH(exp, &exports, next) {
1093 if (strcmp(name, exp->name) == 0) {
1094 return exp;
1095 }
1096 }
1097
1098 return NULL;
1099 }
1100
1101 void nbd_export_set_name(NBDExport *exp, const char *name)
1102 {
1103 if (exp->name == name) {
1104 return;
1105 }
1106
1107 nbd_export_get(exp);
1108 if (exp->name != NULL) {
1109 g_free(exp->name);
1110 exp->name = NULL;
1111 QTAILQ_REMOVE(&exports, exp, next);
1112 nbd_export_put(exp);
1113 }
1114 if (name != NULL) {
1115 nbd_export_get(exp);
1116 exp->name = g_strdup(name);
1117 QTAILQ_INSERT_TAIL(&exports, exp, next);
1118 }
1119 nbd_export_put(exp);
1120 }
1121
1122 void nbd_export_set_description(NBDExport *exp, const char *description)
1123 {
1124 g_free(exp->description);
1125 exp->description = g_strdup(description);
1126 }
1127
1128 void nbd_export_close(NBDExport *exp)
1129 {
1130 NBDClient *client, *next;
1131
1132 nbd_export_get(exp);
1133 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
1134 client_close(client, true);
1135 }
1136 nbd_export_set_name(exp, NULL);
1137 nbd_export_set_description(exp, NULL);
1138 nbd_export_put(exp);
1139 }
1140
1141 void nbd_export_get(NBDExport *exp)
1142 {
1143 assert(exp->refcount > 0);
1144 exp->refcount++;
1145 }
1146
1147 void nbd_export_put(NBDExport *exp)
1148 {
1149 assert(exp->refcount > 0);
1150 if (exp->refcount == 1) {
1151 nbd_export_close(exp);
1152 }
1153
1154 if (--exp->refcount == 0) {
1155 assert(exp->name == NULL);
1156 assert(exp->description == NULL);
1157
1158 if (exp->close) {
1159 exp->close(exp);
1160 }
1161
1162 if (exp->blk) {
1163 if (exp->eject_notifier_blk) {
1164 notifier_remove(&exp->eject_notifier);
1165 blk_unref(exp->eject_notifier_blk);
1166 }
1167 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
1168 blk_aio_detach, exp);
1169 blk_unref(exp->blk);
1170 exp->blk = NULL;
1171 }
1172
1173 g_free(exp);
1174 }
1175 }
1176
1177 BlockBackend *nbd_export_get_blockdev(NBDExport *exp)
1178 {
1179 return exp->blk;
1180 }
1181
1182 void nbd_export_close_all(void)
1183 {
1184 NBDExport *exp, *next;
1185
1186 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {
1187 nbd_export_close(exp);
1188 }
1189 }
1190
1191 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov,
1192 unsigned niov, Error **errp)
1193 {
1194 int ret;
1195
1196 g_assert(qemu_in_coroutine());
1197 qemu_co_mutex_lock(&client->send_lock);
1198 client->send_coroutine = qemu_coroutine_self();
1199
1200 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0;
1201
1202 client->send_coroutine = NULL;
1203 qemu_co_mutex_unlock(&client->send_lock);
1204
1205 return ret;
1206 }
1207
1208 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,
1209 uint64_t handle)
1210 {
1211 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);
1212 stl_be_p(&reply->error, error);
1213 stq_be_p(&reply->handle, handle);
1214 }
1215
1216 static int nbd_co_send_simple_reply(NBDClient *client,
1217 uint64_t handle,
1218 uint32_t error,
1219 void *data,
1220 size_t len,
1221 Error **errp)
1222 {
1223 NBDSimpleReply reply;
1224 int nbd_err = system_errno_to_nbd_errno(error);
1225 struct iovec iov[] = {
1226 {.iov_base = &reply, .iov_len = sizeof(reply)},
1227 {.iov_base = data, .iov_len = len}
1228 };
1229
1230 trace_nbd_co_send_simple_reply(handle, nbd_err, len);
1231 set_be_simple_reply(&reply, nbd_err, handle);
1232
1233 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp);
1234 }
1235
1236 /* nbd_co_receive_request
1237 * Collect a client request. Return 0 if request looks valid, -EIO to drop
1238 * connection right away, and any other negative value to report an error to
1239 * the client (although the caller may still need to disconnect after reporting
1240 * the error).
1241 */
1242 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,
1243 Error **errp)
1244 {
1245 NBDClient *client = req->client;
1246
1247 g_assert(qemu_in_coroutine());
1248 assert(client->recv_coroutine == qemu_coroutine_self());
1249 if (nbd_receive_request(client->ioc, request, errp) < 0) {
1250 return -EIO;
1251 }
1252
1253 trace_nbd_co_receive_request_decode_type(request->handle, request->type,
1254 nbd_cmd_lookup(request->type));
1255
1256 if (request->type != NBD_CMD_WRITE) {
1257 /* No payload, we are ready to read the next request. */
1258 req->complete = true;
1259 }
1260
1261 if (request->type == NBD_CMD_DISC) {
1262 /* Special case: we're going to disconnect without a reply,
1263 * whether or not flags, from, or len are bogus */
1264 return -EIO;
1265 }
1266
1267 /* Check for sanity in the parameters, part 1. Defer as many
1268 * checks as possible until after reading any NBD_CMD_WRITE
1269 * payload, so we can try and keep the connection alive. */
1270 if ((request->from + request->len) < request->from) {
1271 error_setg(errp,
1272 "integer overflow detected, you're probably being attacked");
1273 return -EINVAL;
1274 }
1275
1276 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE) {
1277 if (request->len > NBD_MAX_BUFFER_SIZE) {
1278 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
1279 request->len, NBD_MAX_BUFFER_SIZE);
1280 return -EINVAL;
1281 }
1282
1283 req->data = blk_try_blockalign(client->exp->blk, request->len);
1284 if (req->data == NULL) {
1285 error_setg(errp, "No memory");
1286 return -ENOMEM;
1287 }
1288 }
1289 if (request->type == NBD_CMD_WRITE) {
1290 if (nbd_read(client->ioc, req->data, request->len, errp) < 0) {
1291 error_prepend(errp, "reading from socket failed: ");
1292 return -EIO;
1293 }
1294 req->complete = true;
1295
1296 trace_nbd_co_receive_request_payload_received(request->handle,
1297 request->len);
1298 }
1299
1300 /* Sanity checks, part 2. */
1301 if (request->from + request->len > client->exp->size) {
1302 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32
1303 ", Size: %" PRIu64, request->from, request->len,
1304 (uint64_t)client->exp->size);
1305 return request->type == NBD_CMD_WRITE ? -ENOSPC : -EINVAL;
1306 }
1307 if (request->flags & ~(NBD_CMD_FLAG_FUA | NBD_CMD_FLAG_NO_HOLE)) {
1308 error_setg(errp, "unsupported flags (got 0x%x)", request->flags);
1309 return -EINVAL;
1310 }
1311 if (request->type != NBD_CMD_WRITE_ZEROES &&
1312 (request->flags & NBD_CMD_FLAG_NO_HOLE)) {
1313 error_setg(errp, "unexpected flags (got 0x%x)", request->flags);
1314 return -EINVAL;
1315 }
1316
1317 return 0;
1318 }
1319
1320 /* Owns a reference to the NBDClient passed as opaque. */
1321 static coroutine_fn void nbd_trip(void *opaque)
1322 {
1323 NBDClient *client = opaque;
1324 NBDExport *exp = client->exp;
1325 NBDRequestData *req;
1326 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */
1327 int ret;
1328 int flags;
1329 int reply_data_len = 0;
1330 Error *local_err = NULL;
1331
1332 trace_nbd_trip();
1333 if (client->closing) {
1334 nbd_client_put(client);
1335 return;
1336 }
1337
1338 req = nbd_request_get(client);
1339 ret = nbd_co_receive_request(req, &request, &local_err);
1340 client->recv_coroutine = NULL;
1341 nbd_client_receive_next_request(client);
1342 if (ret == -EIO) {
1343 goto disconnect;
1344 }
1345
1346 if (ret < 0) {
1347 goto reply;
1348 }
1349
1350 if (client->closing) {
1351 /*
1352 * The client may be closed when we are blocked in
1353 * nbd_co_receive_request()
1354 */
1355 goto done;
1356 }
1357
1358 switch (request.type) {
1359 case NBD_CMD_READ:
1360 /* XXX: NBD Protocol only documents use of FUA with WRITE */
1361 if (request.flags & NBD_CMD_FLAG_FUA) {
1362 ret = blk_co_flush(exp->blk);
1363 if (ret < 0) {
1364 error_setg_errno(&local_err, -ret, "flush failed");
1365 break;
1366 }
1367 }
1368
1369 ret = blk_pread(exp->blk, request.from + exp->dev_offset,
1370 req->data, request.len);
1371 if (ret < 0) {
1372 error_setg_errno(&local_err, -ret, "reading from file failed");
1373 break;
1374 }
1375
1376 reply_data_len = request.len;
1377
1378 break;
1379 case NBD_CMD_WRITE:
1380 if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
1381 ret = -EROFS;
1382 break;
1383 }
1384
1385 flags = 0;
1386 if (request.flags & NBD_CMD_FLAG_FUA) {
1387 flags |= BDRV_REQ_FUA;
1388 }
1389 ret = blk_pwrite(exp->blk, request.from + exp->dev_offset,
1390 req->data, request.len, flags);
1391 if (ret < 0) {
1392 error_setg_errno(&local_err, -ret, "writing to file failed");
1393 }
1394
1395 break;
1396 case NBD_CMD_WRITE_ZEROES:
1397 if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
1398 error_setg(&local_err, "Server is read-only, return error");
1399 ret = -EROFS;
1400 break;
1401 }
1402
1403 flags = 0;
1404 if (request.flags & NBD_CMD_FLAG_FUA) {
1405 flags |= BDRV_REQ_FUA;
1406 }
1407 if (!(request.flags & NBD_CMD_FLAG_NO_HOLE)) {
1408 flags |= BDRV_REQ_MAY_UNMAP;
1409 }
1410 ret = blk_pwrite_zeroes(exp->blk, request.from + exp->dev_offset,
1411 request.len, flags);
1412 if (ret < 0) {
1413 error_setg_errno(&local_err, -ret, "writing to file failed");
1414 }
1415
1416 break;
1417 case NBD_CMD_DISC:
1418 /* unreachable, thanks to special case in nbd_co_receive_request() */
1419 abort();
1420
1421 case NBD_CMD_FLUSH:
1422 ret = blk_co_flush(exp->blk);
1423 if (ret < 0) {
1424 error_setg_errno(&local_err, -ret, "flush failed");
1425 }
1426
1427 break;
1428 case NBD_CMD_TRIM:
1429 ret = blk_co_pdiscard(exp->blk, request.from + exp->dev_offset,
1430 request.len);
1431 if (ret < 0) {
1432 error_setg_errno(&local_err, -ret, "discard failed");
1433 }
1434
1435 break;
1436 default:
1437 error_setg(&local_err, "invalid request type (%" PRIu32 ") received",
1438 request.type);
1439 ret = -EINVAL;
1440 }
1441
1442 reply:
1443 if (local_err) {
1444 /* If we get here, local_err was not a fatal error, and should be sent
1445 * to the client. */
1446 error_report_err(local_err);
1447 local_err = NULL;
1448 }
1449
1450 if (nbd_co_send_simple_reply(req->client, request.handle,
1451 ret < 0 ? -ret : 0,
1452 req->data, reply_data_len, &local_err) < 0)
1453 {
1454 error_prepend(&local_err, "Failed to send reply: ");
1455 goto disconnect;
1456 }
1457
1458 /* We must disconnect after NBD_CMD_WRITE if we did not
1459 * read the payload.
1460 */
1461 if (!req->complete) {
1462 error_setg(&local_err, "Request handling failed in intermediate state");
1463 goto disconnect;
1464 }
1465
1466 done:
1467 nbd_request_put(req);
1468 nbd_client_put(client);
1469 return;
1470
1471 disconnect:
1472 if (local_err) {
1473 error_reportf_err(local_err, "Disconnect client, due to: ");
1474 }
1475 nbd_request_put(req);
1476 client_close(client, true);
1477 nbd_client_put(client);
1478 }
1479
1480 static void nbd_client_receive_next_request(NBDClient *client)
1481 {
1482 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) {
1483 nbd_client_get(client);
1484 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
1485 aio_co_schedule(client->exp->ctx, client->recv_coroutine);
1486 }
1487 }
1488
1489 static coroutine_fn void nbd_co_client_start(void *opaque)
1490 {
1491 NBDClient *client = opaque;
1492 NBDExport *exp = client->exp;
1493 Error *local_err = NULL;
1494
1495 if (exp) {
1496 nbd_export_get(exp);
1497 QTAILQ_INSERT_TAIL(&exp->clients, client, next);
1498 }
1499 qemu_co_mutex_init(&client->send_lock);
1500
1501 if (nbd_negotiate(client, &local_err)) {
1502 if (local_err) {
1503 error_report_err(local_err);
1504 }
1505 client_close(client, false);
1506 return;
1507 }
1508
1509 nbd_client_receive_next_request(client);
1510 }
1511
1512 /*
1513 * Create a new client listener on the given export @exp, using the
1514 * given channel @sioc. Begin servicing it in a coroutine. When the
1515 * connection closes, call @close_fn with an indication of whether the
1516 * client completed negotiation.
1517 */
1518 void nbd_client_new(NBDExport *exp,
1519 QIOChannelSocket *sioc,
1520 QCryptoTLSCreds *tlscreds,
1521 const char *tlsaclname,
1522 void (*close_fn)(NBDClient *, bool))
1523 {
1524 NBDClient *client;
1525 Coroutine *co;
1526
1527 client = g_new0(NBDClient, 1);
1528 client->refcount = 1;
1529 client->exp = exp;
1530 client->tlscreds = tlscreds;
1531 if (tlscreds) {
1532 object_ref(OBJECT(client->tlscreds));
1533 }
1534 client->tlsaclname = g_strdup(tlsaclname);
1535 client->sioc = sioc;
1536 object_ref(OBJECT(client->sioc));
1537 client->ioc = QIO_CHANNEL(sioc);
1538 object_ref(OBJECT(client->ioc));
1539 client->close_fn = close_fn;
1540
1541 co = qemu_coroutine_create(nbd_co_client_start, client);
1542 qemu_coroutine_enter(co);
1543 }
QEmu