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nbd/server: Simplify nbd_negotiate_options loop
[qemu/armbru.git] / nbd / server.c
blob2f03059b4cead59cdc51a20e9f2018da328229db
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 EOVERFLOW:
44 return NBD_EOVERFLOW;
45 case ESHUTDOWN:
46 return NBD_ESHUTDOWN;
47 case EINVAL:
48 default:
49 return NBD_EINVAL;
50 }
51 }
52
53 /* Definitions for opaque data types */
54
55 typedef struct NBDRequestData NBDRequestData;
56
57 struct NBDRequestData {
58 QSIMPLEQ_ENTRY(NBDRequestData) entry;
59 NBDClient *client;
60 uint8_t *data;
61 bool complete;
62 };
63
64 struct NBDExport {
65 int refcount;
66 void (*close)(NBDExport *exp);
67
68 BlockBackend *blk;
69 char *name;
70 char *description;
71 off_t dev_offset;
72 off_t size;
73 uint16_t nbdflags;
74 QTAILQ_HEAD(, NBDClient) clients;
75 QTAILQ_ENTRY(NBDExport) next;
76
77 AioContext *ctx;
78
79 BlockBackend *eject_notifier_blk;
80 Notifier eject_notifier;
81 };
82
83 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
84
85 struct NBDClient {
86 int refcount;
87 void (*close_fn)(NBDClient *client, bool negotiated);
88
89 NBDExport *exp;
90 QCryptoTLSCreds *tlscreds;
91 char *tlsaclname;
92 QIOChannelSocket *sioc; /* The underlying data channel */
93 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
94
95 Coroutine *recv_coroutine;
96
97 CoMutex send_lock;
98 Coroutine *send_coroutine;
99
100 QTAILQ_ENTRY(NBDClient) next;
101 int nb_requests;
102 bool closing;
103 };
104
105 /* That's all folks */
106
107 static void nbd_client_receive_next_request(NBDClient *client);
108
109 /* Basic flow for negotiation
110
111 Server Client
112 Negotiate
113
114 or
115
116 Server Client
117 Negotiate #1
118 Option
119 Negotiate #2
120
121 ----
122
123 followed by
124
125 Server Client
126 Request
127 Response
128 Request
129 Response
130 ...
131 ...
132 Request (type == 2)
133
134 */
135
136 /* Send a reply header, including length, but no payload.
137 * Return -errno on error, 0 on success. */
138 static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type,
139 uint32_t opt, uint32_t len, Error **errp)
140 {
141 uint64_t magic;
142
143 trace_nbd_negotiate_send_rep_len(opt, nbd_opt_lookup(opt),
144 type, nbd_rep_lookup(type), len);
145
146 assert(len < NBD_MAX_BUFFER_SIZE);
147 magic = cpu_to_be64(NBD_REP_MAGIC);
148 if (nbd_write(ioc, &magic, sizeof(magic), errp) < 0) {
149 error_prepend(errp, "write failed (rep magic): ");
150 return -EINVAL;
151 }
152
153 opt = cpu_to_be32(opt);
154 if (nbd_write(ioc, &opt, sizeof(opt), errp) < 0) {
155 error_prepend(errp, "write failed (rep opt): ");
156 return -EINVAL;
157 }
158
159 type = cpu_to_be32(type);
160 if (nbd_write(ioc, &type, sizeof(type), errp) < 0) {
161 error_prepend(errp, "write failed (rep type): ");
162 return -EINVAL;
163 }
164
165 len = cpu_to_be32(len);
166 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
167 error_prepend(errp, "write failed (rep data length): ");
168 return -EINVAL;
169 }
170 return 0;
171 }
172
173 /* Send a reply header with default 0 length.
174 * Return -errno on error, 0 on success. */
175 static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt,
176 Error **errp)
177 {
178 return nbd_negotiate_send_rep_len(ioc, type, opt, 0, errp);
179 }
180
181 /* Send an error reply.
182 * Return -errno on error, 0 on success. */
183 static int GCC_FMT_ATTR(5, 6)
184 nbd_negotiate_send_rep_err(QIOChannel *ioc, uint32_t type,
185 uint32_t opt, Error **errp, const char *fmt, ...)
186 {
187 va_list va;
188 char *msg;
189 int ret;
190 size_t len;
191
192 va_start(va, fmt);
193 msg = g_strdup_vprintf(fmt, va);
194 va_end(va);
195 len = strlen(msg);
196 assert(len < 4096);
197 trace_nbd_negotiate_send_rep_err(msg);
198 ret = nbd_negotiate_send_rep_len(ioc, type, opt, len, errp);
199 if (ret < 0) {
200 goto out;
201 }
202 if (nbd_write(ioc, msg, len, errp) < 0) {
203 error_prepend(errp, "write failed (error message): ");
204 ret = -EIO;
205 } else {
206 ret = 0;
207 }
208
209 out:
210 g_free(msg);
211 return ret;
212 }
213
214 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
215 * Return -errno on error, 0 on success. */
216 static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp,
217 Error **errp)
218 {
219 size_t name_len, desc_len;
220 uint32_t len;
221 const char *name = exp->name ? exp->name : "";
222 const char *desc = exp->description ? exp->description : "";
223 int ret;
224
225 trace_nbd_negotiate_send_rep_list(name, desc);
226 name_len = strlen(name);
227 desc_len = strlen(desc);
228 len = name_len + desc_len + sizeof(len);
229 ret = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, len,
230 errp);
231 if (ret < 0) {
232 return ret;
233 }
234
235 len = cpu_to_be32(name_len);
236 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
237 error_prepend(errp, "write failed (name length): ");
238 return -EINVAL;
239 }
240
241 if (nbd_write(ioc, name, name_len, errp) < 0) {
242 error_prepend(errp, "write failed (name buffer): ");
243 return -EINVAL;
244 }
245
246 if (nbd_write(ioc, desc, desc_len, errp) < 0) {
247 error_prepend(errp, "write failed (description buffer): ");
248 return -EINVAL;
249 }
250
251 return 0;
252 }
253
254 /* Process the NBD_OPT_LIST command, with a potential series of replies.
255 * Return -errno on error, 0 on success. */
256 static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length,
257 Error **errp)
258 {
259 NBDExport *exp;
260
261 if (length) {
262 if (nbd_drop(client->ioc, length, errp) < 0) {
263 return -EIO;
264 }
265 return nbd_negotiate_send_rep_err(client->ioc,
266 NBD_REP_ERR_INVALID, NBD_OPT_LIST,
267 errp,
268 "OPT_LIST should not have length");
269 }
270
271 /* For each export, send a NBD_REP_SERVER reply. */
272 QTAILQ_FOREACH(exp, &exports, next) {
273 if (nbd_negotiate_send_rep_list(client->ioc, exp, errp)) {
274 return -EINVAL;
275 }
276 }
277 /* Finish with a NBD_REP_ACK. */
278 return nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_LIST, errp);
279 }
280
281 /* Send a reply to NBD_OPT_EXPORT_NAME.
282 * Return -errno on error, 0 on success. */
283 static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length,
284 uint16_t myflags, bool no_zeroes,
285 Error **errp)
286 {
287 char name[NBD_MAX_NAME_SIZE + 1];
288 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
289 size_t len;
290 int ret;
291
292 /* Client sends:
293 [20 .. xx] export name (length bytes)
294 Server replies:
295 [ 0 .. 7] size
296 [ 8 .. 9] export flags
297 [10 .. 133] reserved (0) [unless no_zeroes]
298 */
299 trace_nbd_negotiate_handle_export_name();
300 if (length >= sizeof(name)) {
301 error_setg(errp, "Bad length received");
302 return -EINVAL;
303 }
304 if (nbd_read(client->ioc, name, length, errp) < 0) {
305 error_prepend(errp, "read failed: ");
306 return -EINVAL;
307 }
308 name[length] = '\0';
309
310 trace_nbd_negotiate_handle_export_name_request(name);
311
312 client->exp = nbd_export_find(name);
313 if (!client->exp) {
314 error_setg(errp, "export not found");
315 return -EINVAL;
316 }
317
318 trace_nbd_negotiate_new_style_size_flags(client->exp->size,
319 client->exp->nbdflags | myflags);
320 stq_be_p(buf, client->exp->size);
321 stw_be_p(buf + 8, client->exp->nbdflags | myflags);
322 len = no_zeroes ? 10 : sizeof(buf);
323 ret = nbd_write(client->ioc, buf, len, errp);
324 if (ret < 0) {
325 error_prepend(errp, "write failed: ");
326 return ret;
327 }
328
329 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
330 nbd_export_get(client->exp);
331
332 return 0;
333 }
334
335 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
336 * The buffer does NOT include the info type prefix.
337 * Return -errno on error, 0 if ready to send more. */
338 static int nbd_negotiate_send_info(NBDClient *client, uint32_t opt,
339 uint16_t info, uint32_t length, void *buf,
340 Error **errp)
341 {
342 int rc;
343
344 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);
345 rc = nbd_negotiate_send_rep_len(client->ioc, NBD_REP_INFO, opt,
346 sizeof(info) + length, errp);
347 if (rc < 0) {
348 return rc;
349 }
350 cpu_to_be16s(&info);
351 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) {
352 return -EIO;
353 }
354 if (nbd_write(client->ioc, buf, length, errp) < 0) {
355 return -EIO;
356 }
357 return 0;
358 }
359
360 /* Handle NBD_OPT_INFO and NBD_OPT_GO.
361 * Return -errno on error, 0 if ready for next option, and 1 to move
362 * into transmission phase. */
363 static int nbd_negotiate_handle_info(NBDClient *client, uint32_t length,
364 uint32_t opt, uint16_t myflags,
365 Error **errp)
366 {
367 int rc;
368 char name[NBD_MAX_NAME_SIZE + 1];
369 NBDExport *exp;
370 uint16_t requests;
371 uint16_t request;
372 uint32_t namelen;
373 bool sendname = false;
374 bool blocksize = false;
375 uint32_t sizes[3];
376 char buf[sizeof(uint64_t) + sizeof(uint16_t)];
377 const char *msg;
378
379 /* Client sends:
380 4 bytes: L, name length (can be 0)
381 L bytes: export name
382 2 bytes: N, number of requests (can be 0)
383 N * 2 bytes: N requests
384 */
385 if (length < sizeof(namelen) + sizeof(requests)) {
386 msg = "overall request too short";
387 goto invalid;
388 }
389 if (nbd_read(client->ioc, &namelen, sizeof(namelen), errp) < 0) {
390 return -EIO;
391 }
392 be32_to_cpus(&namelen);
393 length -= sizeof(namelen);
394 if (namelen > length - sizeof(requests) || (length - namelen) % 2) {
395 msg = "name length is incorrect";
396 goto invalid;
397 }
398 if (nbd_read(client->ioc, name, namelen, errp) < 0) {
399 return -EIO;
400 }
401 name[namelen] = '\0';
402 length -= namelen;
403 trace_nbd_negotiate_handle_export_name_request(name);
404
405 if (nbd_read(client->ioc, &requests, sizeof(requests), errp) < 0) {
406 return -EIO;
407 }
408 be16_to_cpus(&requests);
409 length -= sizeof(requests);
410 trace_nbd_negotiate_handle_info_requests(requests);
411 if (requests != length / sizeof(request)) {
412 msg = "incorrect number of requests for overall length";
413 goto invalid;
414 }
415 while (requests--) {
416 if (nbd_read(client->ioc, &request, sizeof(request), errp) < 0) {
417 return -EIO;
418 }
419 be16_to_cpus(&request);
420 length -= sizeof(request);
421 trace_nbd_negotiate_handle_info_request(request,
422 nbd_info_lookup(request));
423 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;
424 * everything else is either a request we don't know or
425 * something we send regardless of request */
426 switch (request) {
427 case NBD_INFO_NAME:
428 sendname = true;
429 break;
430 case NBD_INFO_BLOCK_SIZE:
431 blocksize = true;
432 break;
433 }
434 }
435
436 exp = nbd_export_find(name);
437 if (!exp) {
438 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_UNKNOWN,
439 opt, errp, "export '%s' not present",
440 name);
441 }
442
443 /* Don't bother sending NBD_INFO_NAME unless client requested it */
444 if (sendname) {
445 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_NAME, length, name,
446 errp);
447 if (rc < 0) {
448 return rc;
449 }
450 }
451
452 /* Send NBD_INFO_DESCRIPTION only if available, regardless of
453 * client request */
454 if (exp->description) {
455 size_t len = strlen(exp->description);
456
457 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_DESCRIPTION,
458 len, exp->description, errp);
459 if (rc < 0) {
460 return rc;
461 }
462 }
463
464 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size
465 * according to whether the client requested it, and according to
466 * whether this is OPT_INFO or OPT_GO. */
467 /* minimum - 1 for back-compat, or 512 if client is new enough.
468 * TODO: consult blk_bs(blk)->bl.request_alignment? */
469 sizes[0] = (opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1;
470 /* preferred - Hard-code to 4096 for now.
471 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */
472 sizes[1] = 4096;
473 /* maximum - At most 32M, but smaller as appropriate. */
474 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE);
475 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]);
476 cpu_to_be32s(&sizes[0]);
477 cpu_to_be32s(&sizes[1]);
478 cpu_to_be32s(&sizes[2]);
479 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_BLOCK_SIZE,
480 sizeof(sizes), sizes, errp);
481 if (rc < 0) {
482 return rc;
483 }
484
485 /* Send NBD_INFO_EXPORT always */
486 trace_nbd_negotiate_new_style_size_flags(exp->size,
487 exp->nbdflags | myflags);
488 stq_be_p(buf, exp->size);
489 stw_be_p(buf + 8, exp->nbdflags | myflags);
490 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_EXPORT,
491 sizeof(buf), buf, errp);
492 if (rc < 0) {
493 return rc;
494 }
495
496 /* If the client is just asking for NBD_OPT_INFO, but forgot to
497 * request block sizes, return an error.
498 * TODO: consult blk_bs(blk)->request_align, and only error if it
499 * is not 1? */
500 if (opt == NBD_OPT_INFO && !blocksize) {
501 return nbd_negotiate_send_rep_err(client->ioc,
502 NBD_REP_ERR_BLOCK_SIZE_REQD, opt,
503 errp,
504 "request NBD_INFO_BLOCK_SIZE to "
505 "use this export");
506 }
507
508 /* Final reply */
509 rc = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, opt, errp);
510 if (rc < 0) {
511 return rc;
512 }
513
514 if (opt == NBD_OPT_GO) {
515 client->exp = exp;
516 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
517 nbd_export_get(client->exp);
518 rc = 1;
519 }
520 return rc;
521
522 invalid:
523 if (nbd_drop(client->ioc, length, errp) < 0) {
524 return -EIO;
525 }
526 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, opt,
527 errp, "%s", msg);
528 }
529
530
531 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
532 * new channel for all further (now-encrypted) communication. */
533 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
534 uint32_t length,
535 Error **errp)
536 {
537 QIOChannel *ioc;
538 QIOChannelTLS *tioc;
539 struct NBDTLSHandshakeData data = { 0 };
540
541 trace_nbd_negotiate_handle_starttls();
542 ioc = client->ioc;
543 if (length) {
544 if (nbd_drop(ioc, length, errp) < 0) {
545 return NULL;
546 }
547 nbd_negotiate_send_rep_err(ioc, NBD_REP_ERR_INVALID, NBD_OPT_STARTTLS,
548 errp,
549 "OPT_STARTTLS should not have length");
550 return NULL;
551 }
552
553 if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK,
554 NBD_OPT_STARTTLS, errp) < 0) {
555 return NULL;
556 }
557
558 tioc = qio_channel_tls_new_server(ioc,
559 client->tlscreds,
560 client->tlsaclname,
561 errp);
562 if (!tioc) {
563 return NULL;
564 }
565
566 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
567 trace_nbd_negotiate_handle_starttls_handshake();
568 data.loop = g_main_loop_new(g_main_context_default(), FALSE);
569 qio_channel_tls_handshake(tioc,
570 nbd_tls_handshake,
571 &data,
572 NULL);
573
574 if (!data.complete) {
575 g_main_loop_run(data.loop);
576 }
577 g_main_loop_unref(data.loop);
578 if (data.error) {
579 object_unref(OBJECT(tioc));
580 error_propagate(errp, data.error);
581 return NULL;
582 }
583
584 return QIO_CHANNEL(tioc);
585 }
586
587 /* nbd_negotiate_options
588 * Process all NBD_OPT_* client option commands, during fixed newstyle
589 * negotiation.
590 * Return:
591 * -errno on error, errp is set
592 * 0 on successful negotiation, errp is not set
593 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
594 * errp is not set
595 */
596 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
597 Error **errp)
598 {
599 uint32_t flags;
600 bool fixedNewstyle = false;
601 bool no_zeroes = false;
602
603 /* Client sends:
604 [ 0 .. 3] client flags
605
606 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO:
607 [ 0 .. 7] NBD_OPTS_MAGIC
608 [ 8 .. 11] NBD option
609 [12 .. 15] Data length
610 ... Rest of request
611
612 [ 0 .. 7] NBD_OPTS_MAGIC
613 [ 8 .. 11] Second NBD option
614 [12 .. 15] Data length
615 ... Rest of request
616 */
617
618 if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) {
619 error_prepend(errp, "read failed: ");
620 return -EIO;
621 }
622 be32_to_cpus(&flags);
623 trace_nbd_negotiate_options_flags(flags);
624 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
625 fixedNewstyle = true;
626 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
627 }
628 if (flags & NBD_FLAG_C_NO_ZEROES) {
629 no_zeroes = true;
630 flags &= ~NBD_FLAG_C_NO_ZEROES;
631 }
632 if (flags != 0) {
633 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);
634 return -EINVAL;
635 }
636
637 while (1) {
638 int ret;
639 uint32_t option, length;
640 uint64_t magic;
641
642 if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) {
643 error_prepend(errp, "read failed: ");
644 return -EINVAL;
645 }
646 magic = be64_to_cpu(magic);
647 trace_nbd_negotiate_options_check_magic(magic);
648 if (magic != NBD_OPTS_MAGIC) {
649 error_setg(errp, "Bad magic received");
650 return -EINVAL;
651 }
652
653 if (nbd_read(client->ioc, &option,
654 sizeof(option), errp) < 0) {
655 error_prepend(errp, "read failed: ");
656 return -EINVAL;
657 }
658 option = be32_to_cpu(option);
659
660 if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) {
661 error_prepend(errp, "read failed: ");
662 return -EINVAL;
663 }
664 length = be32_to_cpu(length);
665
666 trace_nbd_negotiate_options_check_option(option,
667 nbd_opt_lookup(option));
668 if (client->tlscreds &&
669 client->ioc == (QIOChannel *)client->sioc) {
670 QIOChannel *tioc;
671 if (!fixedNewstyle) {
672 error_setg(errp, "Unsupported option 0x%" PRIx32, option);
673 return -EINVAL;
674 }
675 switch (option) {
676 case NBD_OPT_STARTTLS:
677 tioc = nbd_negotiate_handle_starttls(client, length, errp);
678 if (!tioc) {
679 return -EIO;
680 }
681 ret = 0;
682 object_unref(OBJECT(client->ioc));
683 client->ioc = QIO_CHANNEL(tioc);
684 break;
685
686 case NBD_OPT_EXPORT_NAME:
687 /* No way to return an error to client, so drop connection */
688 error_setg(errp, "Option 0x%x not permitted before TLS",
689 option);
690 return -EINVAL;
691
692 default:
693 if (nbd_drop(client->ioc, length, errp) < 0) {
694 return -EIO;
695 }
696 ret = nbd_negotiate_send_rep_err(client->ioc,
697 NBD_REP_ERR_TLS_REQD,
698 option, errp,
699 "Option 0x%" PRIx32
700 "not permitted before TLS",
701 option);
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 break;
715
716 case NBD_OPT_ABORT:
717 /* NBD spec says we must try to reply before
718 * disconnecting, but that we must also tolerate
719 * guests that don't wait for our reply. */
720 nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, option, NULL);
721 return 1;
722
723 case NBD_OPT_EXPORT_NAME:
724 return nbd_negotiate_handle_export_name(client, length,
725 myflags, no_zeroes,
726 errp);
727
728 case NBD_OPT_INFO:
729 case NBD_OPT_GO:
730 ret = nbd_negotiate_handle_info(client, length, option,
731 myflags, errp);
732 if (ret == 1) {
733 assert(option == NBD_OPT_GO);
734 return 0;
735 }
736 break;
737
738 case NBD_OPT_STARTTLS:
739 if (nbd_drop(client->ioc, length, errp) < 0) {
740 return -EIO;
741 }
742 if (client->tlscreds) {
743 ret = nbd_negotiate_send_rep_err(client->ioc,
744 NBD_REP_ERR_INVALID,
745 option, errp,
746 "TLS already enabled");
747 } else {
748 ret = nbd_negotiate_send_rep_err(client->ioc,
749 NBD_REP_ERR_POLICY,
750 option, errp,
751 "TLS not configured");
752 }
753 break;
754 default:
755 if (nbd_drop(client->ioc, length, errp) < 0) {
756 return -EIO;
757 }
758 ret = nbd_negotiate_send_rep_err(client->ioc,
759 NBD_REP_ERR_UNSUP,
760 option, errp,
761 "Unsupported option 0x%"
762 PRIx32 " (%s)", option,
763 nbd_opt_lookup(option));
764 break;
765 }
766 } else {
767 /*
768 * If broken new-style we should drop the connection
769 * for anything except NBD_OPT_EXPORT_NAME
770 */
771 switch (option) {
772 case NBD_OPT_EXPORT_NAME:
773 return nbd_negotiate_handle_export_name(client, length,
774 myflags, no_zeroes,
775 errp);
776
777 default:
778 error_setg(errp, "Unsupported option 0x%" PRIx32 " (%s)",
779 option, nbd_opt_lookup(option));
780 return -EINVAL;
781 }
782 }
783 if (ret < 0) {
784 return ret;
785 }
786 }
787 }
788
789 /* nbd_negotiate
790 * Return:
791 * -errno on error, errp is set
792 * 0 on successful negotiation, errp is not set
793 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
794 * errp is not set
795 */
796 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
797 {
798 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";
799 int ret;
800 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
801 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA |
802 NBD_FLAG_SEND_WRITE_ZEROES);
803 bool oldStyle;
804
805 /* Old style negotiation header, no room for options
806 [ 0 .. 7] passwd ("NBDMAGIC")
807 [ 8 .. 15] magic (NBD_CLIENT_MAGIC)
808 [16 .. 23] size
809 [24 .. 27] export flags (zero-extended)
810 [28 .. 151] reserved (0)
811
812 New style negotiation header, client can send options
813 [ 0 .. 7] passwd ("NBDMAGIC")
814 [ 8 .. 15] magic (NBD_OPTS_MAGIC)
815 [16 .. 17] server flags (0)
816 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO....
817 */
818
819 qio_channel_set_blocking(client->ioc, false, NULL);
820
821 trace_nbd_negotiate_begin();
822 memcpy(buf, "NBDMAGIC", 8);
823
824 oldStyle = client->exp != NULL && !client->tlscreds;
825 if (oldStyle) {
826 trace_nbd_negotiate_old_style(client->exp->size,
827 client->exp->nbdflags | myflags);
828 stq_be_p(buf + 8, NBD_CLIENT_MAGIC);
829 stq_be_p(buf + 16, client->exp->size);
830 stl_be_p(buf + 24, client->exp->nbdflags | myflags);
831
832 if (nbd_write(client->ioc, buf, sizeof(buf), errp) < 0) {
833 error_prepend(errp, "write failed: ");
834 return -EINVAL;
835 }
836 } else {
837 stq_be_p(buf + 8, NBD_OPTS_MAGIC);
838 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);
839
840 if (nbd_write(client->ioc, buf, 18, errp) < 0) {
841 error_prepend(errp, "write failed: ");
842 return -EINVAL;
843 }
844 ret = nbd_negotiate_options(client, myflags, errp);
845 if (ret != 0) {
846 if (ret < 0) {
847 error_prepend(errp, "option negotiation failed: ");
848 }
849 return ret;
850 }
851 }
852
853 trace_nbd_negotiate_success();
854
855 return 0;
856 }
857
858 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request,
859 Error **errp)
860 {
861 uint8_t buf[NBD_REQUEST_SIZE];
862 uint32_t magic;
863 int ret;
864
865 ret = nbd_read(ioc, buf, sizeof(buf), errp);
866 if (ret < 0) {
867 return ret;
868 }
869
870 /* Request
871 [ 0 .. 3] magic (NBD_REQUEST_MAGIC)
872 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...)
873 [ 6 .. 7] type (NBD_CMD_READ, ...)
874 [ 8 .. 15] handle
875 [16 .. 23] from
876 [24 .. 27] len
877 */
878
879 magic = ldl_be_p(buf);
880 request->flags = lduw_be_p(buf + 4);
881 request->type = lduw_be_p(buf + 6);
882 request->handle = ldq_be_p(buf + 8);
883 request->from = ldq_be_p(buf + 16);
884 request->len = ldl_be_p(buf + 24);
885
886 trace_nbd_receive_request(magic, request->flags, request->type,
887 request->from, request->len);
888
889 if (magic != NBD_REQUEST_MAGIC) {
890 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic);
891 return -EINVAL;
892 }
893 return 0;
894 }
895
896 #define MAX_NBD_REQUESTS 16
897
898 void nbd_client_get(NBDClient *client)
899 {
900 client->refcount++;
901 }
902
903 void nbd_client_put(NBDClient *client)
904 {
905 if (--client->refcount == 0) {
906 /* The last reference should be dropped by client->close,
907 * which is called by client_close.
908 */
909 assert(client->closing);
910
911 qio_channel_detach_aio_context(client->ioc);
912 object_unref(OBJECT(client->sioc));
913 object_unref(OBJECT(client->ioc));
914 if (client->tlscreds) {
915 object_unref(OBJECT(client->tlscreds));
916 }
917 g_free(client->tlsaclname);
918 if (client->exp) {
919 QTAILQ_REMOVE(&client->exp->clients, client, next);
920 nbd_export_put(client->exp);
921 }
922 g_free(client);
923 }
924 }
925
926 static void client_close(NBDClient *client, bool negotiated)
927 {
928 if (client->closing) {
929 return;
930 }
931
932 client->closing = true;
933
934 /* Force requests to finish. They will drop their own references,
935 * then we'll close the socket and free the NBDClient.
936 */
937 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
938 NULL);
939
940 /* Also tell the client, so that they release their reference. */
941 if (client->close_fn) {
942 client->close_fn(client, negotiated);
943 }
944 }
945
946 static NBDRequestData *nbd_request_get(NBDClient *client)
947 {
948 NBDRequestData *req;
949
950 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
951 client->nb_requests++;
952
953 req = g_new0(NBDRequestData, 1);
954 nbd_client_get(client);
955 req->client = client;
956 return req;
957 }
958
959 static void nbd_request_put(NBDRequestData *req)
960 {
961 NBDClient *client = req->client;
962
963 if (req->data) {
964 qemu_vfree(req->data);
965 }
966 g_free(req);
967
968 client->nb_requests--;
969 nbd_client_receive_next_request(client);
970
971 nbd_client_put(client);
972 }
973
974 static void blk_aio_attached(AioContext *ctx, void *opaque)
975 {
976 NBDExport *exp = opaque;
977 NBDClient *client;
978
979 trace_nbd_blk_aio_attached(exp->name, ctx);
980
981 exp->ctx = ctx;
982
983 QTAILQ_FOREACH(client, &exp->clients, next) {
984 qio_channel_attach_aio_context(client->ioc, ctx);
985 if (client->recv_coroutine) {
986 aio_co_schedule(ctx, client->recv_coroutine);
987 }
988 if (client->send_coroutine) {
989 aio_co_schedule(ctx, client->send_coroutine);
990 }
991 }
992 }
993
994 static void blk_aio_detach(void *opaque)
995 {
996 NBDExport *exp = opaque;
997 NBDClient *client;
998
999 trace_nbd_blk_aio_detach(exp->name, exp->ctx);
1000
1001 QTAILQ_FOREACH(client, &exp->clients, next) {
1002 qio_channel_detach_aio_context(client->ioc);
1003 }
1004
1005 exp->ctx = NULL;
1006 }
1007
1008 static void nbd_eject_notifier(Notifier *n, void *data)
1009 {
1010 NBDExport *exp = container_of(n, NBDExport, eject_notifier);
1011 nbd_export_close(exp);
1012 }
1013
1014 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
1015 uint16_t nbdflags, void (*close)(NBDExport *),
1016 bool writethrough, BlockBackend *on_eject_blk,
1017 Error **errp)
1018 {
1019 AioContext *ctx;
1020 BlockBackend *blk;
1021 NBDExport *exp = g_new0(NBDExport, 1);
1022 uint64_t perm;
1023 int ret;
1024
1025 /*
1026 * NBD exports are used for non-shared storage migration. Make sure
1027 * that BDRV_O_INACTIVE is cleared and the image is ready for write
1028 * access since the export could be available before migration handover.
1029 */
1030 ctx = bdrv_get_aio_context(bs);
1031 aio_context_acquire(ctx);
1032 bdrv_invalidate_cache(bs, NULL);
1033 aio_context_release(ctx);
1034
1035 /* Don't allow resize while the NBD server is running, otherwise we don't
1036 * care what happens with the node. */
1037 perm = BLK_PERM_CONSISTENT_READ;
1038 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) {
1039 perm |= BLK_PERM_WRITE;
1040 }
1041 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
1042 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD);
1043 ret = blk_insert_bs(blk, bs, errp);
1044 if (ret < 0) {
1045 goto fail;
1046 }
1047 blk_set_enable_write_cache(blk, !writethrough);
1048
1049 exp->refcount = 1;
1050 QTAILQ_INIT(&exp->clients);
1051 exp->blk = blk;
1052 exp->dev_offset = dev_offset;
1053 exp->nbdflags = nbdflags;
1054 exp->size = size < 0 ? blk_getlength(blk) : size;
1055 if (exp->size < 0) {
1056 error_setg_errno(errp, -exp->size,
1057 "Failed to determine the NBD export's length");
1058 goto fail;
1059 }
1060 exp->size -= exp->size % BDRV_SECTOR_SIZE;
1061
1062 exp->close = close;
1063 exp->ctx = blk_get_aio_context(blk);
1064 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
1065
1066 if (on_eject_blk) {
1067 blk_ref(on_eject_blk);
1068 exp->eject_notifier_blk = on_eject_blk;
1069 exp->eject_notifier.notify = nbd_eject_notifier;
1070 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
1071 }
1072 return exp;
1073
1074 fail:
1075 blk_unref(blk);
1076 g_free(exp);
1077 return NULL;
1078 }
1079
1080 NBDExport *nbd_export_find(const char *name)
1081 {
1082 NBDExport *exp;
1083 QTAILQ_FOREACH(exp, &exports, next) {
1084 if (strcmp(name, exp->name) == 0) {
1085 return exp;
1086 }
1087 }
1088
1089 return NULL;
1090 }
1091
1092 void nbd_export_set_name(NBDExport *exp, const char *name)
1093 {
1094 if (exp->name == name) {
1095 return;
1096 }
1097
1098 nbd_export_get(exp);
1099 if (exp->name != NULL) {
1100 g_free(exp->name);
1101 exp->name = NULL;
1102 QTAILQ_REMOVE(&exports, exp, next);
1103 nbd_export_put(exp);
1104 }
1105 if (name != NULL) {
1106 nbd_export_get(exp);
1107 exp->name = g_strdup(name);
1108 QTAILQ_INSERT_TAIL(&exports, exp, next);
1109 }
1110 nbd_export_put(exp);
1111 }
1112
1113 void nbd_export_set_description(NBDExport *exp, const char *description)
1114 {
1115 g_free(exp->description);
1116 exp->description = g_strdup(description);
1117 }
1118
1119 void nbd_export_close(NBDExport *exp)
1120 {
1121 NBDClient *client, *next;
1122
1123 nbd_export_get(exp);
1124 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
1125 client_close(client, true);
1126 }
1127 nbd_export_set_name(exp, NULL);
1128 nbd_export_set_description(exp, NULL);
1129 nbd_export_put(exp);
1130 }
1131
1132 void nbd_export_get(NBDExport *exp)
1133 {
1134 assert(exp->refcount > 0);
1135 exp->refcount++;
1136 }
1137
1138 void nbd_export_put(NBDExport *exp)
1139 {
1140 assert(exp->refcount > 0);
1141 if (exp->refcount == 1) {
1142 nbd_export_close(exp);
1143 }
1144
1145 if (--exp->refcount == 0) {
1146 assert(exp->name == NULL);
1147 assert(exp->description == NULL);
1148
1149 if (exp->close) {
1150 exp->close(exp);
1151 }
1152
1153 if (exp->blk) {
1154 if (exp->eject_notifier_blk) {
1155 notifier_remove(&exp->eject_notifier);
1156 blk_unref(exp->eject_notifier_blk);
1157 }
1158 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
1159 blk_aio_detach, exp);
1160 blk_unref(exp->blk);
1161 exp->blk = NULL;
1162 }
1163
1164 g_free(exp);
1165 }
1166 }
1167
1168 BlockBackend *nbd_export_get_blockdev(NBDExport *exp)
1169 {
1170 return exp->blk;
1171 }
1172
1173 void nbd_export_close_all(void)
1174 {
1175 NBDExport *exp, *next;
1176
1177 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {
1178 nbd_export_close(exp);
1179 }
1180 }
1181
1182 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov,
1183 unsigned niov, Error **errp)
1184 {
1185 int ret;
1186
1187 g_assert(qemu_in_coroutine());
1188 qemu_co_mutex_lock(&client->send_lock);
1189 client->send_coroutine = qemu_coroutine_self();
1190
1191 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0;
1192
1193 client->send_coroutine = NULL;
1194 qemu_co_mutex_unlock(&client->send_lock);
1195
1196 return ret;
1197 }
1198
1199 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,
1200 uint64_t handle)
1201 {
1202 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);
1203 stl_be_p(&reply->error, error);
1204 stq_be_p(&reply->handle, handle);
1205 }
1206
1207 static int nbd_co_send_simple_reply(NBDClient *client,
1208 uint64_t handle,
1209 uint32_t error,
1210 void *data,
1211 size_t len,
1212 Error **errp)
1213 {
1214 NBDSimpleReply reply;
1215 int nbd_err = system_errno_to_nbd_errno(error);
1216 struct iovec iov[] = {
1217 {.iov_base = &reply, .iov_len = sizeof(reply)},
1218 {.iov_base = data, .iov_len = len}
1219 };
1220
1221 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err),
1222 len);
1223 set_be_simple_reply(&reply, nbd_err, handle);
1224
1225 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp);
1226 }
1227
1228 /* nbd_co_receive_request
1229 * Collect a client request. Return 0 if request looks valid, -EIO to drop
1230 * connection right away, and any other negative value to report an error to
1231 * the client (although the caller may still need to disconnect after reporting
1232 * the error).
1233 */
1234 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,
1235 Error **errp)
1236 {
1237 NBDClient *client = req->client;
1238
1239 g_assert(qemu_in_coroutine());
1240 assert(client->recv_coroutine == qemu_coroutine_self());
1241 if (nbd_receive_request(client->ioc, request, errp) < 0) {
1242 return -EIO;
1243 }
1244
1245 trace_nbd_co_receive_request_decode_type(request->handle, request->type,
1246 nbd_cmd_lookup(request->type));
1247
1248 if (request->type != NBD_CMD_WRITE) {
1249 /* No payload, we are ready to read the next request. */
1250 req->complete = true;
1251 }
1252
1253 if (request->type == NBD_CMD_DISC) {
1254 /* Special case: we're going to disconnect without a reply,
1255 * whether or not flags, from, or len are bogus */
1256 return -EIO;
1257 }
1258
1259 /* Check for sanity in the parameters, part 1. Defer as many
1260 * checks as possible until after reading any NBD_CMD_WRITE
1261 * payload, so we can try and keep the connection alive. */
1262 if ((request->from + request->len) < request->from) {
1263 error_setg(errp,
1264 "integer overflow detected, you're probably being attacked");
1265 return -EINVAL;
1266 }
1267
1268 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE) {
1269 if (request->len > NBD_MAX_BUFFER_SIZE) {
1270 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
1271 request->len, NBD_MAX_BUFFER_SIZE);
1272 return -EINVAL;
1273 }
1274
1275 req->data = blk_try_blockalign(client->exp->blk, request->len);
1276 if (req->data == NULL) {
1277 error_setg(errp, "No memory");
1278 return -ENOMEM;
1279 }
1280 }
1281 if (request->type == NBD_CMD_WRITE) {
1282 if (nbd_read(client->ioc, req->data, request->len, errp) < 0) {
1283 error_prepend(errp, "reading from socket failed: ");
1284 return -EIO;
1285 }
1286 req->complete = true;
1287
1288 trace_nbd_co_receive_request_payload_received(request->handle,
1289 request->len);
1290 }
1291
1292 /* Sanity checks, part 2. */
1293 if (request->from + request->len > client->exp->size) {
1294 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32
1295 ", Size: %" PRIu64, request->from, request->len,
1296 (uint64_t)client->exp->size);
1297 return request->type == NBD_CMD_WRITE ? -ENOSPC : -EINVAL;
1298 }
1299 if (request->flags & ~(NBD_CMD_FLAG_FUA | NBD_CMD_FLAG_NO_HOLE)) {
1300 error_setg(errp, "unsupported flags (got 0x%x)", request->flags);
1301 return -EINVAL;
1302 }
1303 if (request->type != NBD_CMD_WRITE_ZEROES &&
1304 (request->flags & NBD_CMD_FLAG_NO_HOLE)) {
1305 error_setg(errp, "unexpected flags (got 0x%x)", request->flags);
1306 return -EINVAL;
1307 }
1308
1309 return 0;
1310 }
1311
1312 /* Owns a reference to the NBDClient passed as opaque. */
1313 static coroutine_fn void nbd_trip(void *opaque)
1314 {
1315 NBDClient *client = opaque;
1316 NBDExport *exp = client->exp;
1317 NBDRequestData *req;
1318 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */
1319 int ret;
1320 int flags;
1321 int reply_data_len = 0;
1322 Error *local_err = NULL;
1323
1324 trace_nbd_trip();
1325 if (client->closing) {
1326 nbd_client_put(client);
1327 return;
1328 }
1329
1330 req = nbd_request_get(client);
1331 ret = nbd_co_receive_request(req, &request, &local_err);
1332 client->recv_coroutine = NULL;
1333 nbd_client_receive_next_request(client);
1334 if (ret == -EIO) {
1335 goto disconnect;
1336 }
1337
1338 if (ret < 0) {
1339 goto reply;
1340 }
1341
1342 if (client->closing) {
1343 /*
1344 * The client may be closed when we are blocked in
1345 * nbd_co_receive_request()
1346 */
1347 goto done;
1348 }
1349
1350 switch (request.type) {
1351 case NBD_CMD_READ:
1352 /* XXX: NBD Protocol only documents use of FUA with WRITE */
1353 if (request.flags & NBD_CMD_FLAG_FUA) {
1354 ret = blk_co_flush(exp->blk);
1355 if (ret < 0) {
1356 error_setg_errno(&local_err, -ret, "flush failed");
1357 break;
1358 }
1359 }
1360
1361 ret = blk_pread(exp->blk, request.from + exp->dev_offset,
1362 req->data, request.len);
1363 if (ret < 0) {
1364 error_setg_errno(&local_err, -ret, "reading from file failed");
1365 break;
1366 }
1367
1368 reply_data_len = request.len;
1369
1370 break;
1371 case NBD_CMD_WRITE:
1372 if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
1373 error_setg(&local_err, "Export is read-only");
1374 ret = -EROFS;
1375 break;
1376 }
1377
1378 flags = 0;
1379 if (request.flags & NBD_CMD_FLAG_FUA) {
1380 flags |= BDRV_REQ_FUA;
1381 }
1382 ret = blk_pwrite(exp->blk, request.from + exp->dev_offset,
1383 req->data, request.len, flags);
1384 if (ret < 0) {
1385 error_setg_errno(&local_err, -ret, "writing to file failed");
1386 }
1387
1388 break;
1389 case NBD_CMD_WRITE_ZEROES:
1390 if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
1391 error_setg(&local_err, "Export is read-only");
1392 ret = -EROFS;
1393 break;
1394 }
1395
1396 flags = 0;
1397 if (request.flags & NBD_CMD_FLAG_FUA) {
1398 flags |= BDRV_REQ_FUA;
1399 }
1400 if (!(request.flags & NBD_CMD_FLAG_NO_HOLE)) {
1401 flags |= BDRV_REQ_MAY_UNMAP;
1402 }
1403 ret = blk_pwrite_zeroes(exp->blk, request.from + exp->dev_offset,
1404 request.len, flags);
1405 if (ret < 0) {
1406 error_setg_errno(&local_err, -ret, "writing to file failed");
1407 }
1408
1409 break;
1410 case NBD_CMD_DISC:
1411 /* unreachable, thanks to special case in nbd_co_receive_request() */
1412 abort();
1413
1414 case NBD_CMD_FLUSH:
1415 ret = blk_co_flush(exp->blk);
1416 if (ret < 0) {
1417 error_setg_errno(&local_err, -ret, "flush failed");
1418 }
1419
1420 break;
1421 case NBD_CMD_TRIM:
1422 ret = blk_co_pdiscard(exp->blk, request.from + exp->dev_offset,
1423 request.len);
1424 if (ret < 0) {
1425 error_setg_errno(&local_err, -ret, "discard failed");
1426 }
1427
1428 break;
1429 default:
1430 error_setg(&local_err, "invalid request type (%" PRIu32 ") received",
1431 request.type);
1432 ret = -EINVAL;
1433 }
1434
1435 reply:
1436 if (local_err) {
1437 /* If we get here, local_err was not a fatal error, and should be sent
1438 * to the client. */
1439 error_report_err(local_err);
1440 local_err = NULL;
1441 }
1442
1443 if (nbd_co_send_simple_reply(req->client, request.handle,
1444 ret < 0 ? -ret : 0,
1445 req->data, reply_data_len, &local_err) < 0)
1446 {
1447 error_prepend(&local_err, "Failed to send reply: ");
1448 goto disconnect;
1449 }
1450
1451 /* We must disconnect after NBD_CMD_WRITE if we did not
1452 * read the payload.
1453 */
1454 if (!req->complete) {
1455 error_setg(&local_err, "Request handling failed in intermediate state");
1456 goto disconnect;
1457 }
1458
1459 done:
1460 nbd_request_put(req);
1461 nbd_client_put(client);
1462 return;
1463
1464 disconnect:
1465 if (local_err) {
1466 error_reportf_err(local_err, "Disconnect client, due to: ");
1467 }
1468 nbd_request_put(req);
1469 client_close(client, true);
1470 nbd_client_put(client);
1471 }
1472
1473 static void nbd_client_receive_next_request(NBDClient *client)
1474 {
1475 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) {
1476 nbd_client_get(client);
1477 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
1478 aio_co_schedule(client->exp->ctx, client->recv_coroutine);
1479 }
1480 }
1481
1482 static coroutine_fn void nbd_co_client_start(void *opaque)
1483 {
1484 NBDClient *client = opaque;
1485 NBDExport *exp = client->exp;
1486 Error *local_err = NULL;
1487
1488 if (exp) {
1489 nbd_export_get(exp);
1490 QTAILQ_INSERT_TAIL(&exp->clients, client, next);
1491 }
1492 qemu_co_mutex_init(&client->send_lock);
1493
1494 if (nbd_negotiate(client, &local_err)) {
1495 if (local_err) {
1496 error_report_err(local_err);
1497 }
1498 client_close(client, false);
1499 return;
1500 }
1501
1502 nbd_client_receive_next_request(client);
1503 }
1504
1505 /*
1506 * Create a new client listener on the given export @exp, using the
1507 * given channel @sioc. Begin servicing it in a coroutine. When the
1508 * connection closes, call @close_fn with an indication of whether the
1509 * client completed negotiation.
1510 */
1511 void nbd_client_new(NBDExport *exp,
1512 QIOChannelSocket *sioc,
1513 QCryptoTLSCreds *tlscreds,
1514 const char *tlsaclname,
1515 void (*close_fn)(NBDClient *, bool))
1516 {
1517 NBDClient *client;
1518 Coroutine *co;
1519
1520 client = g_new0(NBDClient, 1);
1521 client->refcount = 1;
1522 client->exp = exp;
1523 client->tlscreds = tlscreds;
1524 if (tlscreds) {
1525 object_ref(OBJECT(client->tlscreds));
1526 }
1527 client->tlsaclname = g_strdup(tlsaclname);
1528 client->sioc = sioc;
1529 object_ref(OBJECT(client->sioc));
1530 client->ioc = QIO_CHANNEL(sioc);
1531 object_ref(OBJECT(client->ioc));
1532 client->close_fn = close_fn;
1533
1534 co = qemu_coroutine_create(nbd_co_client_start, client);
1535 qemu_coroutine_enter(co);
1536 }
armbru's QEMU hackery