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tests: Simplify abstract-interfaces check with a helper
[qemu/kevin.git] / nbd / server.c
blob49ed57455cd91b5a22b69c6801ad86cba52e7d31
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[8 + 4 + 124] = "";
287 size_t len;
288 int ret;
289
290 /* Client sends:
291 [20 .. xx] export name (length bytes)
292 */
293 trace_nbd_negotiate_handle_export_name();
294 if (length >= sizeof(name)) {
295 error_setg(errp, "Bad length received");
296 return -EINVAL;
297 }
298 if (nbd_read(client->ioc, name, length, errp) < 0) {
299 error_prepend(errp, "read failed: ");
300 return -EINVAL;
301 }
302 name[length] = '\0';
303
304 trace_nbd_negotiate_handle_export_name_request(name);
305
306 client->exp = nbd_export_find(name);
307 if (!client->exp) {
308 error_setg(errp, "export not found");
309 return -EINVAL;
310 }
311
312 trace_nbd_negotiate_new_style_size_flags(client->exp->size,
313 client->exp->nbdflags | myflags);
314 stq_be_p(buf, client->exp->size);
315 stw_be_p(buf + 8, client->exp->nbdflags | myflags);
316 len = no_zeroes ? 10 : sizeof(buf);
317 ret = nbd_write(client->ioc, buf, len, errp);
318 if (ret < 0) {
319 error_prepend(errp, "write failed: ");
320 return ret;
321 }
322
323 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
324 nbd_export_get(client->exp);
325
326 return 0;
327 }
328
329 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
330 * The buffer does NOT include the info type prefix.
331 * Return -errno on error, 0 if ready to send more. */
332 static int nbd_negotiate_send_info(NBDClient *client, uint32_t opt,
333 uint16_t info, uint32_t length, void *buf,
334 Error **errp)
335 {
336 int rc;
337
338 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);
339 rc = nbd_negotiate_send_rep_len(client->ioc, NBD_REP_INFO, opt,
340 sizeof(info) + length, errp);
341 if (rc < 0) {
342 return rc;
343 }
344 cpu_to_be16s(&info);
345 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) {
346 return -EIO;
347 }
348 if (nbd_write(client->ioc, buf, length, errp) < 0) {
349 return -EIO;
350 }
351 return 0;
352 }
353
354 /* Handle NBD_OPT_INFO and NBD_OPT_GO.
355 * Return -errno on error, 0 if ready for next option, and 1 to move
356 * into transmission phase. */
357 static int nbd_negotiate_handle_info(NBDClient *client, uint32_t length,
358 uint32_t opt, uint16_t myflags,
359 Error **errp)
360 {
361 int rc;
362 char name[NBD_MAX_NAME_SIZE + 1];
363 NBDExport *exp;
364 uint16_t requests;
365 uint16_t request;
366 uint32_t namelen;
367 bool sendname = false;
368 bool blocksize = false;
369 uint32_t sizes[3];
370 char buf[sizeof(uint64_t) + sizeof(uint16_t)];
371 const char *msg;
372
373 /* Client sends:
374 4 bytes: L, name length (can be 0)
375 L bytes: export name
376 2 bytes: N, number of requests (can be 0)
377 N * 2 bytes: N requests
378 */
379 if (length < sizeof(namelen) + sizeof(requests)) {
380 msg = "overall request too short";
381 goto invalid;
382 }
383 if (nbd_read(client->ioc, &namelen, sizeof(namelen), errp) < 0) {
384 return -EIO;
385 }
386 be32_to_cpus(&namelen);
387 length -= sizeof(namelen);
388 if (namelen > length - sizeof(requests) || (length - namelen) % 2) {
389 msg = "name length is incorrect";
390 goto invalid;
391 }
392 if (nbd_read(client->ioc, name, namelen, errp) < 0) {
393 return -EIO;
394 }
395 name[namelen] = '\0';
396 length -= namelen;
397 trace_nbd_negotiate_handle_export_name_request(name);
398
399 if (nbd_read(client->ioc, &requests, sizeof(requests), errp) < 0) {
400 return -EIO;
401 }
402 be16_to_cpus(&requests);
403 length -= sizeof(requests);
404 trace_nbd_negotiate_handle_info_requests(requests);
405 if (requests != length / sizeof(request)) {
406 msg = "incorrect number of requests for overall length";
407 goto invalid;
408 }
409 while (requests--) {
410 if (nbd_read(client->ioc, &request, sizeof(request), errp) < 0) {
411 return -EIO;
412 }
413 be16_to_cpus(&request);
414 length -= sizeof(request);
415 trace_nbd_negotiate_handle_info_request(request,
416 nbd_info_lookup(request));
417 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;
418 * everything else is either a request we don't know or
419 * something we send regardless of request */
420 switch (request) {
421 case NBD_INFO_NAME:
422 sendname = true;
423 break;
424 case NBD_INFO_BLOCK_SIZE:
425 blocksize = true;
426 break;
427 }
428 }
429
430 exp = nbd_export_find(name);
431 if (!exp) {
432 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_UNKNOWN,
433 opt, errp, "export '%s' not present",
434 name);
435 }
436
437 /* Don't bother sending NBD_INFO_NAME unless client requested it */
438 if (sendname) {
439 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_NAME, length, name,
440 errp);
441 if (rc < 0) {
442 return rc;
443 }
444 }
445
446 /* Send NBD_INFO_DESCRIPTION only if available, regardless of
447 * client request */
448 if (exp->description) {
449 size_t len = strlen(exp->description);
450
451 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_DESCRIPTION,
452 len, exp->description, errp);
453 if (rc < 0) {
454 return rc;
455 }
456 }
457
458 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size
459 * according to whether the client requested it, and according to
460 * whether this is OPT_INFO or OPT_GO. */
461 /* minimum - 1 for back-compat, or 512 if client is new enough.
462 * TODO: consult blk_bs(blk)->bl.request_alignment? */
463 sizes[0] = (opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1;
464 /* preferred - Hard-code to 4096 for now.
465 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */
466 sizes[1] = 4096;
467 /* maximum - At most 32M, but smaller as appropriate. */
468 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE);
469 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]);
470 cpu_to_be32s(&sizes[0]);
471 cpu_to_be32s(&sizes[1]);
472 cpu_to_be32s(&sizes[2]);
473 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_BLOCK_SIZE,
474 sizeof(sizes), sizes, errp);
475 if (rc < 0) {
476 return rc;
477 }
478
479 /* Send NBD_INFO_EXPORT always */
480 trace_nbd_negotiate_new_style_size_flags(exp->size,
481 exp->nbdflags | myflags);
482 stq_be_p(buf, exp->size);
483 stw_be_p(buf + 8, exp->nbdflags | myflags);
484 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_EXPORT,
485 sizeof(buf), buf, errp);
486 if (rc < 0) {
487 return rc;
488 }
489
490 /* If the client is just asking for NBD_OPT_INFO, but forgot to
491 * request block sizes, return an error.
492 * TODO: consult blk_bs(blk)->request_align, and only error if it
493 * is not 1? */
494 if (opt == NBD_OPT_INFO && !blocksize) {
495 return nbd_negotiate_send_rep_err(client->ioc,
496 NBD_REP_ERR_BLOCK_SIZE_REQD, opt,
497 errp,
498 "request NBD_INFO_BLOCK_SIZE to "
499 "use this export");
500 }
501
502 /* Final reply */
503 rc = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, opt, errp);
504 if (rc < 0) {
505 return rc;
506 }
507
508 if (opt == NBD_OPT_GO) {
509 client->exp = exp;
510 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
511 nbd_export_get(client->exp);
512 rc = 1;
513 }
514 return rc;
515
516 invalid:
517 if (nbd_drop(client->ioc, length, errp) < 0) {
518 return -EIO;
519 }
520 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, opt,
521 errp, "%s", msg);
522 }
523
524
525 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
526 * new channel for all further (now-encrypted) communication. */
527 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
528 uint32_t length,
529 Error **errp)
530 {
531 QIOChannel *ioc;
532 QIOChannelTLS *tioc;
533 struct NBDTLSHandshakeData data = { 0 };
534
535 trace_nbd_negotiate_handle_starttls();
536 ioc = client->ioc;
537 if (length) {
538 if (nbd_drop(ioc, length, errp) < 0) {
539 return NULL;
540 }
541 nbd_negotiate_send_rep_err(ioc, NBD_REP_ERR_INVALID, NBD_OPT_STARTTLS,
542 errp,
543 "OPT_STARTTLS should not have length");
544 return NULL;
545 }
546
547 if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK,
548 NBD_OPT_STARTTLS, errp) < 0) {
549 return NULL;
550 }
551
552 tioc = qio_channel_tls_new_server(ioc,
553 client->tlscreds,
554 client->tlsaclname,
555 errp);
556 if (!tioc) {
557 return NULL;
558 }
559
560 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
561 trace_nbd_negotiate_handle_starttls_handshake();
562 data.loop = g_main_loop_new(g_main_context_default(), FALSE);
563 qio_channel_tls_handshake(tioc,
564 nbd_tls_handshake,
565 &data,
566 NULL);
567
568 if (!data.complete) {
569 g_main_loop_run(data.loop);
570 }
571 g_main_loop_unref(data.loop);
572 if (data.error) {
573 object_unref(OBJECT(tioc));
574 error_propagate(errp, data.error);
575 return NULL;
576 }
577
578 return QIO_CHANNEL(tioc);
579 }
580
581 /* nbd_negotiate_options
582 * Process all NBD_OPT_* client option commands, during fixed newstyle
583 * negotiation.
584 * Return:
585 * -errno on error, errp is set
586 * 0 on successful negotiation, errp is not set
587 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
588 * errp is not set
589 */
590 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
591 Error **errp)
592 {
593 uint32_t flags;
594 bool fixedNewstyle = false;
595 bool no_zeroes = false;
596
597 /* Client sends:
598 [ 0 .. 3] client flags
599
600 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO:
601 [ 0 .. 7] NBD_OPTS_MAGIC
602 [ 8 .. 11] NBD option
603 [12 .. 15] Data length
604 ... Rest of request
605
606 [ 0 .. 7] NBD_OPTS_MAGIC
607 [ 8 .. 11] Second NBD option
608 [12 .. 15] Data length
609 ... Rest of request
610 */
611
612 if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) {
613 error_prepend(errp, "read failed: ");
614 return -EIO;
615 }
616 be32_to_cpus(&flags);
617 trace_nbd_negotiate_options_flags(flags);
618 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
619 fixedNewstyle = true;
620 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
621 }
622 if (flags & NBD_FLAG_C_NO_ZEROES) {
623 no_zeroes = true;
624 flags &= ~NBD_FLAG_C_NO_ZEROES;
625 }
626 if (flags != 0) {
627 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);
628 return -EINVAL;
629 }
630
631 while (1) {
632 int ret;
633 uint32_t option, length;
634 uint64_t magic;
635
636 if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) {
637 error_prepend(errp, "read failed: ");
638 return -EINVAL;
639 }
640 magic = be64_to_cpu(magic);
641 trace_nbd_negotiate_options_check_magic(magic);
642 if (magic != NBD_OPTS_MAGIC) {
643 error_setg(errp, "Bad magic received");
644 return -EINVAL;
645 }
646
647 if (nbd_read(client->ioc, &option,
648 sizeof(option), errp) < 0) {
649 error_prepend(errp, "read failed: ");
650 return -EINVAL;
651 }
652 option = be32_to_cpu(option);
653
654 if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) {
655 error_prepend(errp, "read failed: ");
656 return -EINVAL;
657 }
658 length = be32_to_cpu(length);
659
660 trace_nbd_negotiate_options_check_option(option,
661 nbd_opt_lookup(option));
662 if (client->tlscreds &&
663 client->ioc == (QIOChannel *)client->sioc) {
664 QIOChannel *tioc;
665 if (!fixedNewstyle) {
666 error_setg(errp, "Unsupported option 0x%" PRIx32, option);
667 return -EINVAL;
668 }
669 switch (option) {
670 case NBD_OPT_STARTTLS:
671 tioc = nbd_negotiate_handle_starttls(client, length, errp);
672 if (!tioc) {
673 return -EIO;
674 }
675 object_unref(OBJECT(client->ioc));
676 client->ioc = QIO_CHANNEL(tioc);
677 break;
678
679 case NBD_OPT_EXPORT_NAME:
680 /* No way to return an error to client, so drop connection */
681 error_setg(errp, "Option 0x%x not permitted before TLS",
682 option);
683 return -EINVAL;
684
685 default:
686 if (nbd_drop(client->ioc, length, errp) < 0) {
687 return -EIO;
688 }
689 ret = nbd_negotiate_send_rep_err(client->ioc,
690 NBD_REP_ERR_TLS_REQD,
691 option, errp,
692 "Option 0x%" PRIx32
693 "not permitted before TLS",
694 option);
695 if (ret < 0) {
696 return ret;
697 }
698 /* Let the client keep trying, unless they asked to
699 * quit. In this mode, we've already sent an error, so
700 * we can't ack the abort. */
701 if (option == NBD_OPT_ABORT) {
702 return 1;
703 }
704 break;
705 }
706 } else if (fixedNewstyle) {
707 switch (option) {
708 case NBD_OPT_LIST:
709 ret = nbd_negotiate_handle_list(client, length, errp);
710 if (ret < 0) {
711 return ret;
712 }
713 break;
714
715 case NBD_OPT_ABORT:
716 /* NBD spec says we must try to reply before
717 * disconnecting, but that we must also tolerate
718 * guests that don't wait for our reply. */
719 nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, option, NULL);
720 return 1;
721
722 case NBD_OPT_EXPORT_NAME:
723 return nbd_negotiate_handle_export_name(client, length,
724 myflags, no_zeroes,
725 errp);
726
727 case NBD_OPT_INFO:
728 case NBD_OPT_GO:
729 ret = nbd_negotiate_handle_info(client, length, option,
730 myflags, errp);
731 if (ret == 1) {
732 assert(option == NBD_OPT_GO);
733 return 0;
734 }
735 if (ret) {
736 return ret;
737 }
738 break;
739
740 case NBD_OPT_STARTTLS:
741 if (nbd_drop(client->ioc, length, errp) < 0) {
742 return -EIO;
743 }
744 if (client->tlscreds) {
745 ret = nbd_negotiate_send_rep_err(client->ioc,
746 NBD_REP_ERR_INVALID,
747 option, errp,
748 "TLS already enabled");
749 } else {
750 ret = nbd_negotiate_send_rep_err(client->ioc,
751 NBD_REP_ERR_POLICY,
752 option, errp,
753 "TLS not configured");
754 }
755 if (ret < 0) {
756 return ret;
757 }
758 break;
759 default:
760 if (nbd_drop(client->ioc, length, errp) < 0) {
761 return -EIO;
762 }
763 ret = nbd_negotiate_send_rep_err(client->ioc,
764 NBD_REP_ERR_UNSUP,
765 option, errp,
766 "Unsupported option 0x%"
767 PRIx32 " (%s)", option,
768 nbd_opt_lookup(option));
769 if (ret < 0) {
770 return ret;
771 }
772 break;
773 }
774 } else {
775 /*
776 * If broken new-style we should drop the connection
777 * for anything except NBD_OPT_EXPORT_NAME
778 */
779 switch (option) {
780 case NBD_OPT_EXPORT_NAME:
781 return nbd_negotiate_handle_export_name(client, length,
782 myflags, no_zeroes,
783 errp);
784
785 default:
786 error_setg(errp, "Unsupported option 0x%" PRIx32 " (%s)",
787 option, nbd_opt_lookup(option));
788 return -EINVAL;
789 }
790 }
791 }
792 }
793
794 /* nbd_negotiate
795 * Return:
796 * -errno on error, errp is set
797 * 0 on successful negotiation, errp is not set
798 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
799 * errp is not set
800 */
801 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
802 {
803 char buf[8 + 8 + 8 + 128];
804 int ret;
805 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
806 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA |
807 NBD_FLAG_SEND_WRITE_ZEROES);
808 bool oldStyle;
809
810 /* Old style negotiation header without options
811 [ 0 .. 7] passwd ("NBDMAGIC")
812 [ 8 .. 15] magic (NBD_CLIENT_MAGIC)
813 [16 .. 23] size
814 [24 .. 25] server flags (0)
815 [26 .. 27] export flags
816 [28 .. 151] reserved (0)
817
818 New style negotiation header with options
819 [ 0 .. 7] passwd ("NBDMAGIC")
820 [ 8 .. 15] magic (NBD_OPTS_MAGIC)
821 [16 .. 17] server flags (0)
822 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO....
823 */
824
825 qio_channel_set_blocking(client->ioc, false, NULL);
826
827 trace_nbd_negotiate_begin();
828 memset(buf, 0, sizeof(buf));
829 memcpy(buf, "NBDMAGIC", 8);
830
831 oldStyle = client->exp != NULL && !client->tlscreds;
832 if (oldStyle) {
833 trace_nbd_negotiate_old_style(client->exp->size,
834 client->exp->nbdflags | myflags);
835 stq_be_p(buf + 8, NBD_CLIENT_MAGIC);
836 stq_be_p(buf + 16, client->exp->size);
837 stw_be_p(buf + 26, client->exp->nbdflags | myflags);
838
839 if (nbd_write(client->ioc, buf, sizeof(buf), errp) < 0) {
840 error_prepend(errp, "write failed: ");
841 return -EINVAL;
842 }
843 } else {
844 stq_be_p(buf + 8, NBD_OPTS_MAGIC);
845 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);
846
847 if (nbd_write(client->ioc, buf, 18, errp) < 0) {
848 error_prepend(errp, "write failed: ");
849 return -EINVAL;
850 }
851 ret = nbd_negotiate_options(client, myflags, errp);
852 if (ret != 0) {
853 if (ret < 0) {
854 error_prepend(errp, "option negotiation failed: ");
855 }
856 return ret;
857 }
858 }
859
860 trace_nbd_negotiate_success();
861
862 return 0;
863 }
864
865 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request,
866 Error **errp)
867 {
868 uint8_t buf[NBD_REQUEST_SIZE];
869 uint32_t magic;
870 int ret;
871
872 ret = nbd_read(ioc, buf, sizeof(buf), errp);
873 if (ret < 0) {
874 return ret;
875 }
876
877 /* Request
878 [ 0 .. 3] magic (NBD_REQUEST_MAGIC)
879 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...)
880 [ 6 .. 7] type (NBD_CMD_READ, ...)
881 [ 8 .. 15] handle
882 [16 .. 23] from
883 [24 .. 27] len
884 */
885
886 magic = ldl_be_p(buf);
887 request->flags = lduw_be_p(buf + 4);
888 request->type = lduw_be_p(buf + 6);
889 request->handle = ldq_be_p(buf + 8);
890 request->from = ldq_be_p(buf + 16);
891 request->len = ldl_be_p(buf + 24);
892
893 trace_nbd_receive_request(magic, request->flags, request->type,
894 request->from, request->len);
895
896 if (magic != NBD_REQUEST_MAGIC) {
897 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic);
898 return -EINVAL;
899 }
900 return 0;
901 }
902
903 static int nbd_send_reply(QIOChannel *ioc, NBDReply *reply, Error **errp)
904 {
905 uint8_t buf[NBD_REPLY_SIZE];
906
907 reply->error = system_errno_to_nbd_errno(reply->error);
908
909 trace_nbd_send_reply(reply->error, reply->handle);
910
911 /* Reply
912 [ 0 .. 3] magic (NBD_REPLY_MAGIC)
913 [ 4 .. 7] error (0 == no error)
914 [ 7 .. 15] handle
915 */
916 stl_be_p(buf, NBD_REPLY_MAGIC);
917 stl_be_p(buf + 4, reply->error);
918 stq_be_p(buf + 8, reply->handle);
919
920 return nbd_write(ioc, buf, sizeof(buf), errp);
921 }
922
923 #define MAX_NBD_REQUESTS 16
924
925 void nbd_client_get(NBDClient *client)
926 {
927 client->refcount++;
928 }
929
930 void nbd_client_put(NBDClient *client)
931 {
932 if (--client->refcount == 0) {
933 /* The last reference should be dropped by client->close,
934 * which is called by client_close.
935 */
936 assert(client->closing);
937
938 qio_channel_detach_aio_context(client->ioc);
939 object_unref(OBJECT(client->sioc));
940 object_unref(OBJECT(client->ioc));
941 if (client->tlscreds) {
942 object_unref(OBJECT(client->tlscreds));
943 }
944 g_free(client->tlsaclname);
945 if (client->exp) {
946 QTAILQ_REMOVE(&client->exp->clients, client, next);
947 nbd_export_put(client->exp);
948 }
949 g_free(client);
950 }
951 }
952
953 static void client_close(NBDClient *client, bool negotiated)
954 {
955 if (client->closing) {
956 return;
957 }
958
959 client->closing = true;
960
961 /* Force requests to finish. They will drop their own references,
962 * then we'll close the socket and free the NBDClient.
963 */
964 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
965 NULL);
966
967 /* Also tell the client, so that they release their reference. */
968 if (client->close_fn) {
969 client->close_fn(client, negotiated);
970 }
971 }
972
973 static NBDRequestData *nbd_request_get(NBDClient *client)
974 {
975 NBDRequestData *req;
976
977 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
978 client->nb_requests++;
979
980 req = g_new0(NBDRequestData, 1);
981 nbd_client_get(client);
982 req->client = client;
983 return req;
984 }
985
986 static void nbd_request_put(NBDRequestData *req)
987 {
988 NBDClient *client = req->client;
989
990 if (req->data) {
991 qemu_vfree(req->data);
992 }
993 g_free(req);
994
995 client->nb_requests--;
996 nbd_client_receive_next_request(client);
997
998 nbd_client_put(client);
999 }
1000
1001 static void blk_aio_attached(AioContext *ctx, void *opaque)
1002 {
1003 NBDExport *exp = opaque;
1004 NBDClient *client;
1005
1006 trace_nbd_blk_aio_attached(exp->name, ctx);
1007
1008 exp->ctx = ctx;
1009
1010 QTAILQ_FOREACH(client, &exp->clients, next) {
1011 qio_channel_attach_aio_context(client->ioc, ctx);
1012 if (client->recv_coroutine) {
1013 aio_co_schedule(ctx, client->recv_coroutine);
1014 }
1015 if (client->send_coroutine) {
1016 aio_co_schedule(ctx, client->send_coroutine);
1017 }
1018 }
1019 }
1020
1021 static void blk_aio_detach(void *opaque)
1022 {
1023 NBDExport *exp = opaque;
1024 NBDClient *client;
1025
1026 trace_nbd_blk_aio_detach(exp->name, exp->ctx);
1027
1028 QTAILQ_FOREACH(client, &exp->clients, next) {
1029 qio_channel_detach_aio_context(client->ioc);
1030 }
1031
1032 exp->ctx = NULL;
1033 }
1034
1035 static void nbd_eject_notifier(Notifier *n, void *data)
1036 {
1037 NBDExport *exp = container_of(n, NBDExport, eject_notifier);
1038 nbd_export_close(exp);
1039 }
1040
1041 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
1042 uint16_t nbdflags, void (*close)(NBDExport *),
1043 bool writethrough, BlockBackend *on_eject_blk,
1044 Error **errp)
1045 {
1046 BlockBackend *blk;
1047 NBDExport *exp = g_malloc0(sizeof(NBDExport));
1048 uint64_t perm;
1049 int ret;
1050
1051 /* Don't allow resize while the NBD server is running, otherwise we don't
1052 * care what happens with the node. */
1053 perm = BLK_PERM_CONSISTENT_READ;
1054 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) {
1055 perm |= BLK_PERM_WRITE;
1056 }
1057 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
1058 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD);
1059 ret = blk_insert_bs(blk, bs, errp);
1060 if (ret < 0) {
1061 goto fail;
1062 }
1063 blk_set_enable_write_cache(blk, !writethrough);
1064
1065 exp->refcount = 1;
1066 QTAILQ_INIT(&exp->clients);
1067 exp->blk = blk;
1068 exp->dev_offset = dev_offset;
1069 exp->nbdflags = nbdflags;
1070 exp->size = size < 0 ? blk_getlength(blk) : size;
1071 if (exp->size < 0) {
1072 error_setg_errno(errp, -exp->size,
1073 "Failed to determine the NBD export's length");
1074 goto fail;
1075 }
1076 exp->size -= exp->size % BDRV_SECTOR_SIZE;
1077
1078 exp->close = close;
1079 exp->ctx = blk_get_aio_context(blk);
1080 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
1081
1082 if (on_eject_blk) {
1083 blk_ref(on_eject_blk);
1084 exp->eject_notifier_blk = on_eject_blk;
1085 exp->eject_notifier.notify = nbd_eject_notifier;
1086 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
1087 }
1088
1089 /*
1090 * NBD exports are used for non-shared storage migration. Make sure
1091 * that BDRV_O_INACTIVE is cleared and the image is ready for write
1092 * access since the export could be available before migration handover.
1093 */
1094 aio_context_acquire(exp->ctx);
1095 blk_invalidate_cache(blk, NULL);
1096 aio_context_release(exp->ctx);
1097 return exp;
1098
1099 fail:
1100 blk_unref(blk);
1101 g_free(exp);
1102 return NULL;
1103 }
1104
1105 NBDExport *nbd_export_find(const char *name)
1106 {
1107 NBDExport *exp;
1108 QTAILQ_FOREACH(exp, &exports, next) {
1109 if (strcmp(name, exp->name) == 0) {
1110 return exp;
1111 }
1112 }
1113
1114 return NULL;
1115 }
1116
1117 void nbd_export_set_name(NBDExport *exp, const char *name)
1118 {
1119 if (exp->name == name) {
1120 return;
1121 }
1122
1123 nbd_export_get(exp);
1124 if (exp->name != NULL) {
1125 g_free(exp->name);
1126 exp->name = NULL;
1127 QTAILQ_REMOVE(&exports, exp, next);
1128 nbd_export_put(exp);
1129 }
1130 if (name != NULL) {
1131 nbd_export_get(exp);
1132 exp->name = g_strdup(name);
1133 QTAILQ_INSERT_TAIL(&exports, exp, next);
1134 }
1135 nbd_export_put(exp);
1136 }
1137
1138 void nbd_export_set_description(NBDExport *exp, const char *description)
1139 {
1140 g_free(exp->description);
1141 exp->description = g_strdup(description);
1142 }
1143
1144 void nbd_export_close(NBDExport *exp)
1145 {
1146 NBDClient *client, *next;
1147
1148 nbd_export_get(exp);
1149 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
1150 client_close(client, true);
1151 }
1152 nbd_export_set_name(exp, NULL);
1153 nbd_export_set_description(exp, NULL);
1154 nbd_export_put(exp);
1155 }
1156
1157 void nbd_export_get(NBDExport *exp)
1158 {
1159 assert(exp->refcount > 0);
1160 exp->refcount++;
1161 }
1162
1163 void nbd_export_put(NBDExport *exp)
1164 {
1165 assert(exp->refcount > 0);
1166 if (exp->refcount == 1) {
1167 nbd_export_close(exp);
1168 }
1169
1170 if (--exp->refcount == 0) {
1171 assert(exp->name == NULL);
1172 assert(exp->description == NULL);
1173
1174 if (exp->close) {
1175 exp->close(exp);
1176 }
1177
1178 if (exp->blk) {
1179 if (exp->eject_notifier_blk) {
1180 notifier_remove(&exp->eject_notifier);
1181 blk_unref(exp->eject_notifier_blk);
1182 }
1183 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
1184 blk_aio_detach, exp);
1185 blk_unref(exp->blk);
1186 exp->blk = NULL;
1187 }
1188
1189 g_free(exp);
1190 }
1191 }
1192
1193 BlockBackend *nbd_export_get_blockdev(NBDExport *exp)
1194 {
1195 return exp->blk;
1196 }
1197
1198 void nbd_export_close_all(void)
1199 {
1200 NBDExport *exp, *next;
1201
1202 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {
1203 nbd_export_close(exp);
1204 }
1205 }
1206
1207 static int nbd_co_send_reply(NBDRequestData *req, NBDReply *reply, int len,
1208 Error **errp)
1209 {
1210 NBDClient *client = req->client;
1211 int ret;
1212
1213 g_assert(qemu_in_coroutine());
1214
1215 trace_nbd_co_send_reply(reply->handle, reply->error, len);
1216
1217 qemu_co_mutex_lock(&client->send_lock);
1218 client->send_coroutine = qemu_coroutine_self();
1219
1220 if (!len) {
1221 ret = nbd_send_reply(client->ioc, reply, errp);
1222 } else {
1223 qio_channel_set_cork(client->ioc, true);
1224 ret = nbd_send_reply(client->ioc, reply, errp);
1225 if (ret == 0) {
1226 ret = nbd_write(client->ioc, req->data, len, errp);
1227 if (ret < 0) {
1228 ret = -EIO;
1229 }
1230 }
1231 qio_channel_set_cork(client->ioc, false);
1232 }
1233
1234 client->send_coroutine = NULL;
1235 qemu_co_mutex_unlock(&client->send_lock);
1236 return ret;
1237 }
1238
1239 /* nbd_co_receive_request
1240 * Collect a client request. Return 0 if request looks valid, -EIO to drop
1241 * connection right away, and any other negative value to report an error to
1242 * the client (although the caller may still need to disconnect after reporting
1243 * the error).
1244 */
1245 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,
1246 Error **errp)
1247 {
1248 NBDClient *client = req->client;
1249
1250 g_assert(qemu_in_coroutine());
1251 assert(client->recv_coroutine == qemu_coroutine_self());
1252 if (nbd_receive_request(client->ioc, request, errp) < 0) {
1253 return -EIO;
1254 }
1255
1256 trace_nbd_co_receive_request_decode_type(request->handle, request->type,
1257 nbd_cmd_lookup(request->type));
1258
1259 if (request->type != NBD_CMD_WRITE) {
1260 /* No payload, we are ready to read the next request. */
1261 req->complete = true;
1262 }
1263
1264 if (request->type == NBD_CMD_DISC) {
1265 /* Special case: we're going to disconnect without a reply,
1266 * whether or not flags, from, or len are bogus */
1267 return -EIO;
1268 }
1269
1270 /* Check for sanity in the parameters, part 1. Defer as many
1271 * checks as possible until after reading any NBD_CMD_WRITE
1272 * payload, so we can try and keep the connection alive. */
1273 if ((request->from + request->len) < request->from) {
1274 error_setg(errp,
1275 "integer overflow detected, you're probably being attacked");
1276 return -EINVAL;
1277 }
1278
1279 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE) {
1280 if (request->len > NBD_MAX_BUFFER_SIZE) {
1281 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
1282 request->len, NBD_MAX_BUFFER_SIZE);
1283 return -EINVAL;
1284 }
1285
1286 req->data = blk_try_blockalign(client->exp->blk, request->len);
1287 if (req->data == NULL) {
1288 error_setg(errp, "No memory");
1289 return -ENOMEM;
1290 }
1291 }
1292 if (request->type == NBD_CMD_WRITE) {
1293 if (nbd_read(client->ioc, req->data, request->len, errp) < 0) {
1294 error_prepend(errp, "reading from socket failed: ");
1295 return -EIO;
1296 }
1297 req->complete = true;
1298
1299 trace_nbd_co_receive_request_payload_received(request->handle,
1300 request->len);
1301 }
1302
1303 /* Sanity checks, part 2. */
1304 if (request->from + request->len > client->exp->size) {
1305 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32
1306 ", Size: %" PRIu64, request->from, request->len,
1307 (uint64_t)client->exp->size);
1308 return request->type == NBD_CMD_WRITE ? -ENOSPC : -EINVAL;
1309 }
1310 if (request->flags & ~(NBD_CMD_FLAG_FUA | NBD_CMD_FLAG_NO_HOLE)) {
1311 error_setg(errp, "unsupported flags (got 0x%x)", request->flags);
1312 return -EINVAL;
1313 }
1314 if (request->type != NBD_CMD_WRITE_ZEROES &&
1315 (request->flags & NBD_CMD_FLAG_NO_HOLE)) {
1316 error_setg(errp, "unexpected flags (got 0x%x)", request->flags);
1317 return -EINVAL;
1318 }
1319
1320 return 0;
1321 }
1322
1323 /* Owns a reference to the NBDClient passed as opaque. */
1324 static coroutine_fn void nbd_trip(void *opaque)
1325 {
1326 NBDClient *client = opaque;
1327 NBDExport *exp = client->exp;
1328 NBDRequestData *req;
1329 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */
1330 NBDReply reply;
1331 int ret;
1332 int flags;
1333 int reply_data_len = 0;
1334 Error *local_err = NULL;
1335
1336 trace_nbd_trip();
1337 if (client->closing) {
1338 nbd_client_put(client);
1339 return;
1340 }
1341
1342 req = nbd_request_get(client);
1343 ret = nbd_co_receive_request(req, &request, &local_err);
1344 client->recv_coroutine = NULL;
1345 nbd_client_receive_next_request(client);
1346 if (ret == -EIO) {
1347 goto disconnect;
1348 }
1349
1350 reply.handle = request.handle;
1351 reply.error = 0;
1352
1353 if (ret < 0) {
1354 reply.error = -ret;
1355 goto reply;
1356 }
1357
1358 if (client->closing) {
1359 /*
1360 * The client may be closed when we are blocked in
1361 * nbd_co_receive_request()
1362 */
1363 goto done;
1364 }
1365
1366 switch (request.type) {
1367 case NBD_CMD_READ:
1368 /* XXX: NBD Protocol only documents use of FUA with WRITE */
1369 if (request.flags & NBD_CMD_FLAG_FUA) {
1370 ret = blk_co_flush(exp->blk);
1371 if (ret < 0) {
1372 error_setg_errno(&local_err, -ret, "flush failed");
1373 reply.error = -ret;
1374 break;
1375 }
1376 }
1377
1378 ret = blk_pread(exp->blk, request.from + exp->dev_offset,
1379 req->data, request.len);
1380 if (ret < 0) {
1381 error_setg_errno(&local_err, -ret, "reading from file failed");
1382 reply.error = -ret;
1383 break;
1384 }
1385
1386 reply_data_len = request.len;
1387
1388 break;
1389 case NBD_CMD_WRITE:
1390 if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
1391 reply.error = EROFS;
1392 break;
1393 }
1394
1395 flags = 0;
1396 if (request.flags & NBD_CMD_FLAG_FUA) {
1397 flags |= BDRV_REQ_FUA;
1398 }
1399 ret = blk_pwrite(exp->blk, request.from + exp->dev_offset,
1400 req->data, request.len, flags);
1401 if (ret < 0) {
1402 error_setg_errno(&local_err, -ret, "writing to file failed");
1403 reply.error = -ret;
1404 }
1405
1406 break;
1407 case NBD_CMD_WRITE_ZEROES:
1408 if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
1409 error_setg(&local_err, "Server is read-only, return error");
1410 reply.error = EROFS;
1411 break;
1412 }
1413
1414 flags = 0;
1415 if (request.flags & NBD_CMD_FLAG_FUA) {
1416 flags |= BDRV_REQ_FUA;
1417 }
1418 if (!(request.flags & NBD_CMD_FLAG_NO_HOLE)) {
1419 flags |= BDRV_REQ_MAY_UNMAP;
1420 }
1421 ret = blk_pwrite_zeroes(exp->blk, request.from + exp->dev_offset,
1422 request.len, flags);
1423 if (ret < 0) {
1424 error_setg_errno(&local_err, -ret, "writing to file failed");
1425 reply.error = -ret;
1426 }
1427
1428 break;
1429 case NBD_CMD_DISC:
1430 /* unreachable, thanks to special case in nbd_co_receive_request() */
1431 abort();
1432
1433 case NBD_CMD_FLUSH:
1434 ret = blk_co_flush(exp->blk);
1435 if (ret < 0) {
1436 error_setg_errno(&local_err, -ret, "flush failed");
1437 reply.error = -ret;
1438 }
1439
1440 break;
1441 case NBD_CMD_TRIM:
1442 ret = blk_co_pdiscard(exp->blk, request.from + exp->dev_offset,
1443 request.len);
1444 if (ret < 0) {
1445 error_setg_errno(&local_err, -ret, "discard failed");
1446 reply.error = -ret;
1447 }
1448
1449 break;
1450 default:
1451 error_setg(&local_err, "invalid request type (%" PRIu32 ") received",
1452 request.type);
1453 reply.error = EINVAL;
1454 }
1455
1456 reply:
1457 if (local_err) {
1458 /* If we are here local_err is not fatal error, already stored in
1459 * reply.error */
1460 error_report_err(local_err);
1461 local_err = NULL;
1462 }
1463
1464 if (nbd_co_send_reply(req, &reply, reply_data_len, &local_err) < 0) {
1465 error_prepend(&local_err, "Failed to send reply: ");
1466 goto disconnect;
1467 }
1468
1469 /* We must disconnect after NBD_CMD_WRITE if we did not
1470 * read the payload.
1471 */
1472 if (!req->complete) {
1473 error_setg(&local_err, "Request handling failed in intermediate state");
1474 goto disconnect;
1475 }
1476
1477 done:
1478 nbd_request_put(req);
1479 nbd_client_put(client);
1480 return;
1481
1482 disconnect:
1483 if (local_err) {
1484 error_reportf_err(local_err, "Disconnect client, due to: ");
1485 }
1486 nbd_request_put(req);
1487 client_close(client, true);
1488 nbd_client_put(client);
1489 }
1490
1491 static void nbd_client_receive_next_request(NBDClient *client)
1492 {
1493 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) {
1494 nbd_client_get(client);
1495 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
1496 aio_co_schedule(client->exp->ctx, client->recv_coroutine);
1497 }
1498 }
1499
1500 static coroutine_fn void nbd_co_client_start(void *opaque)
1501 {
1502 NBDClient *client = opaque;
1503 NBDExport *exp = client->exp;
1504 Error *local_err = NULL;
1505
1506 if (exp) {
1507 nbd_export_get(exp);
1508 QTAILQ_INSERT_TAIL(&exp->clients, client, next);
1509 }
1510 qemu_co_mutex_init(&client->send_lock);
1511
1512 if (nbd_negotiate(client, &local_err)) {
1513 if (local_err) {
1514 error_report_err(local_err);
1515 }
1516 client_close(client, false);
1517 return;
1518 }
1519
1520 nbd_client_receive_next_request(client);
1521 }
1522
1523 /*
1524 * Create a new client listener on the given export @exp, using the
1525 * given channel @sioc. Begin servicing it in a coroutine. When the
1526 * connection closes, call @close_fn with an indication of whether the
1527 * client completed negotiation.
1528 */
1529 void nbd_client_new(NBDExport *exp,
1530 QIOChannelSocket *sioc,
1531 QCryptoTLSCreds *tlscreds,
1532 const char *tlsaclname,
1533 void (*close_fn)(NBDClient *, bool))
1534 {
1535 NBDClient *client;
1536 Coroutine *co;
1537
1538 client = g_malloc0(sizeof(NBDClient));
1539 client->refcount = 1;
1540 client->exp = exp;
1541 client->tlscreds = tlscreds;
1542 if (tlscreds) {
1543 object_ref(OBJECT(client->tlscreds));
1544 }
1545 client->tlsaclname = g_strdup(tlsaclname);
1546 client->sioc = sioc;
1547 object_ref(OBJECT(client->sioc));
1548 client->ioc = QIO_CHANNEL(sioc);
1549 object_ref(OBJECT(client->ioc));
1550 client->close_fn = close_fn;
1551
1552 co = qemu_coroutine_create(nbd_co_client_start, client);
1553 qemu_coroutine_enter(co);
1554 }
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