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hw/microblaze/zynqmp: Use object_initialize_child for correct ref. counting
[qemu/ar7.git] / nbd / server.c
blobe21bd501dc632b574165af2165c7d71912687f1c
1 /*
2 * Copyright (C) 2016-2018 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 #define NBD_META_ID_BASE_ALLOCATION 0
26 #define NBD_META_ID_DIRTY_BITMAP 1
27
28 /* NBD_MAX_BITMAP_EXTENTS: 1 mb of extents data. An empirical
29 * constant. If an increase is needed, note that the NBD protocol
30 * recommends no larger than 32 mb, so that the client won't consider
31 * the reply as a denial of service attack. */
32 #define NBD_MAX_BITMAP_EXTENTS (0x100000 / 8)
33
34 static int system_errno_to_nbd_errno(int err)
35 {
36 switch (err) {
37 case 0:
38 return NBD_SUCCESS;
39 case EPERM:
40 case EROFS:
41 return NBD_EPERM;
42 case EIO:
43 return NBD_EIO;
44 case ENOMEM:
45 return NBD_ENOMEM;
46 #ifdef EDQUOT
47 case EDQUOT:
48 #endif
49 case EFBIG:
50 case ENOSPC:
51 return NBD_ENOSPC;
52 case EOVERFLOW:
53 return NBD_EOVERFLOW;
54 case ESHUTDOWN:
55 return NBD_ESHUTDOWN;
56 case EINVAL:
57 default:
58 return NBD_EINVAL;
59 }
60 }
61
62 /* Definitions for opaque data types */
63
64 typedef struct NBDRequestData NBDRequestData;
65
66 struct NBDRequestData {
67 QSIMPLEQ_ENTRY(NBDRequestData) entry;
68 NBDClient *client;
69 uint8_t *data;
70 bool complete;
71 };
72
73 struct NBDExport {
74 int refcount;
75 void (*close)(NBDExport *exp);
76
77 BlockBackend *blk;
78 char *name;
79 char *description;
80 uint64_t dev_offset;
81 uint64_t size;
82 uint16_t nbdflags;
83 QTAILQ_HEAD(, NBDClient) clients;
84 QTAILQ_ENTRY(NBDExport) next;
85
86 AioContext *ctx;
87
88 BlockBackend *eject_notifier_blk;
89 Notifier eject_notifier;
90
91 BdrvDirtyBitmap *export_bitmap;
92 char *export_bitmap_context;
93 };
94
95 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
96
97 /* NBDExportMetaContexts represents a list of contexts to be exported,
98 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for
99 * NBD_OPT_LIST_META_CONTEXT. */
100 typedef struct NBDExportMetaContexts {
101 NBDExport *exp;
102 bool valid; /* means that negotiation of the option finished without
103 errors */
104 bool base_allocation; /* export base:allocation context (block status) */
105 bool bitmap; /* export qemu:dirty-bitmap:<export bitmap name> */
106 } NBDExportMetaContexts;
107
108 struct NBDClient {
109 int refcount;
110 void (*close_fn)(NBDClient *client, bool negotiated);
111
112 NBDExport *exp;
113 QCryptoTLSCreds *tlscreds;
114 char *tlsauthz;
115 QIOChannelSocket *sioc; /* The underlying data channel */
116 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
117
118 Coroutine *recv_coroutine;
119
120 CoMutex send_lock;
121 Coroutine *send_coroutine;
122
123 QTAILQ_ENTRY(NBDClient) next;
124 int nb_requests;
125 bool closing;
126
127 uint32_t check_align; /* If non-zero, check for aligned client requests */
128
129 bool structured_reply;
130 NBDExportMetaContexts export_meta;
131
132 uint32_t opt; /* Current option being negotiated */
133 uint32_t optlen; /* remaining length of data in ioc for the option being
134 negotiated now */
135 };
136
137 static void nbd_client_receive_next_request(NBDClient *client);
138
139 /* Basic flow for negotiation
140
141 Server Client
142 Negotiate
143
144 or
145
146 Server Client
147 Negotiate #1
148 Option
149 Negotiate #2
150
151 ----
152
153 followed by
154
155 Server Client
156 Request
157 Response
158 Request
159 Response
160 ...
161 ...
162 Request (type == 2)
163
164 */
165
166 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option,
167 uint32_t type, uint32_t length)
168 {
169 stq_be_p(&rep->magic, NBD_REP_MAGIC);
170 stl_be_p(&rep->option, option);
171 stl_be_p(&rep->type, type);
172 stl_be_p(&rep->length, length);
173 }
174
175 /* Send a reply header, including length, but no payload.
176 * Return -errno on error, 0 on success. */
177 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type,
178 uint32_t len, Error **errp)
179 {
180 NBDOptionReply rep;
181
182 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt),
183 type, nbd_rep_lookup(type), len);
184
185 assert(len < NBD_MAX_BUFFER_SIZE);
186
187 set_be_option_rep(&rep, client->opt, type, len);
188 return nbd_write(client->ioc, &rep, sizeof(rep), errp);
189 }
190
191 /* Send a reply header with default 0 length.
192 * Return -errno on error, 0 on success. */
193 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type,
194 Error **errp)
195 {
196 return nbd_negotiate_send_rep_len(client, type, 0, errp);
197 }
198
199 /* Send an error reply.
200 * Return -errno on error, 0 on success. */
201 static int GCC_FMT_ATTR(4, 0)
202 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,
203 Error **errp, const char *fmt, va_list va)
204 {
205 char *msg;
206 int ret;
207 size_t len;
208
209 msg = g_strdup_vprintf(fmt, va);
210 len = strlen(msg);
211 assert(len < 4096);
212 trace_nbd_negotiate_send_rep_err(msg);
213 ret = nbd_negotiate_send_rep_len(client, type, len, errp);
214 if (ret < 0) {
215 goto out;
216 }
217 if (nbd_write(client->ioc, msg, len, errp) < 0) {
218 error_prepend(errp, "write failed (error message): ");
219 ret = -EIO;
220 } else {
221 ret = 0;
222 }
223
224 out:
225 g_free(msg);
226 return ret;
227 }
228
229 /* Send an error reply.
230 * Return -errno on error, 0 on success. */
231 static int GCC_FMT_ATTR(4, 5)
232 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type,
233 Error **errp, const char *fmt, ...)
234 {
235 va_list va;
236 int ret;
237
238 va_start(va, fmt);
239 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
240 va_end(va);
241 return ret;
242 }
243
244 /* Drop remainder of the current option, and send a reply with the
245 * given error type and message. Return -errno on read or write
246 * failure; or 0 if connection is still live. */
247 static int GCC_FMT_ATTR(4, 0)
248 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp,
249 const char *fmt, va_list va)
250 {
251 int ret = nbd_drop(client->ioc, client->optlen, errp);
252
253 client->optlen = 0;
254 if (!ret) {
255 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
256 }
257 return ret;
258 }
259
260 static int GCC_FMT_ATTR(4, 5)
261 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp,
262 const char *fmt, ...)
263 {
264 int ret;
265 va_list va;
266
267 va_start(va, fmt);
268 ret = nbd_opt_vdrop(client, type, errp, fmt, va);
269 va_end(va);
270
271 return ret;
272 }
273
274 static int GCC_FMT_ATTR(3, 4)
275 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...)
276 {
277 int ret;
278 va_list va;
279
280 va_start(va, fmt);
281 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va);
282 va_end(va);
283
284 return ret;
285 }
286
287 /* Read size bytes from the unparsed payload of the current option.
288 * Return -errno on I/O error, 0 if option was completely handled by
289 * sending a reply about inconsistent lengths, or 1 on success. */
290 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size,
291 Error **errp)
292 {
293 if (size > client->optlen) {
294 return nbd_opt_invalid(client, errp,
295 "Inconsistent lengths in option %s",
296 nbd_opt_lookup(client->opt));
297 }
298 client->optlen -= size;
299 return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1;
300 }
301
302 /* Drop size bytes from the unparsed payload of the current option.
303 * Return -errno on I/O error, 0 if option was completely handled by
304 * sending a reply about inconsistent lengths, or 1 on success. */
305 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp)
306 {
307 if (size > client->optlen) {
308 return nbd_opt_invalid(client, errp,
309 "Inconsistent lengths in option %s",
310 nbd_opt_lookup(client->opt));
311 }
312 client->optlen -= size;
313 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1;
314 }
315
316 /* nbd_opt_read_name
317 *
318 * Read a string with the format:
319 * uint32_t len (<= NBD_MAX_NAME_SIZE)
320 * len bytes string (not 0-terminated)
321 *
322 * @name should be enough to store NBD_MAX_NAME_SIZE+1.
323 * If @length is non-null, it will be set to the actual string length.
324 *
325 * Return -errno on I/O error, 0 if option was completely handled by
326 * sending a reply about inconsistent lengths, or 1 on success.
327 */
328 static int nbd_opt_read_name(NBDClient *client, char *name, uint32_t *length,
329 Error **errp)
330 {
331 int ret;
332 uint32_t len;
333
334 ret = nbd_opt_read(client, &len, sizeof(len), errp);
335 if (ret <= 0) {
336 return ret;
337 }
338 len = cpu_to_be32(len);
339
340 if (len > NBD_MAX_NAME_SIZE) {
341 return nbd_opt_invalid(client, errp,
342 "Invalid name length: %" PRIu32, len);
343 }
344
345 ret = nbd_opt_read(client, name, len, errp);
346 if (ret <= 0) {
347 return ret;
348 }
349 name[len] = '\0';
350
351 if (length) {
352 *length = len;
353 }
354
355 return 1;
356 }
357
358 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
359 * Return -errno on error, 0 on success. */
360 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp,
361 Error **errp)
362 {
363 size_t name_len, desc_len;
364 uint32_t len;
365 const char *name = exp->name ? exp->name : "";
366 const char *desc = exp->description ? exp->description : "";
367 QIOChannel *ioc = client->ioc;
368 int ret;
369
370 trace_nbd_negotiate_send_rep_list(name, desc);
371 name_len = strlen(name);
372 desc_len = strlen(desc);
373 len = name_len + desc_len + sizeof(len);
374 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp);
375 if (ret < 0) {
376 return ret;
377 }
378
379 len = cpu_to_be32(name_len);
380 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
381 error_prepend(errp, "write failed (name length): ");
382 return -EINVAL;
383 }
384
385 if (nbd_write(ioc, name, name_len, errp) < 0) {
386 error_prepend(errp, "write failed (name buffer): ");
387 return -EINVAL;
388 }
389
390 if (nbd_write(ioc, desc, desc_len, errp) < 0) {
391 error_prepend(errp, "write failed (description buffer): ");
392 return -EINVAL;
393 }
394
395 return 0;
396 }
397
398 /* Process the NBD_OPT_LIST command, with a potential series of replies.
399 * Return -errno on error, 0 on success. */
400 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)
401 {
402 NBDExport *exp;
403 assert(client->opt == NBD_OPT_LIST);
404
405 /* For each export, send a NBD_REP_SERVER reply. */
406 QTAILQ_FOREACH(exp, &exports, next) {
407 if (nbd_negotiate_send_rep_list(client, exp, errp)) {
408 return -EINVAL;
409 }
410 }
411 /* Finish with a NBD_REP_ACK. */
412 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
413 }
414
415 static void nbd_check_meta_export(NBDClient *client)
416 {
417 client->export_meta.valid &= client->exp == client->export_meta.exp;
418 }
419
420 /* Send a reply to NBD_OPT_EXPORT_NAME.
421 * Return -errno on error, 0 on success. */
422 static int nbd_negotiate_handle_export_name(NBDClient *client,
423 uint16_t myflags, bool no_zeroes,
424 Error **errp)
425 {
426 char name[NBD_MAX_NAME_SIZE + 1];
427 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
428 size_t len;
429 int ret;
430
431 /* Client sends:
432 [20 .. xx] export name (length bytes)
433 Server replies:
434 [ 0 .. 7] size
435 [ 8 .. 9] export flags
436 [10 .. 133] reserved (0) [unless no_zeroes]
437 */
438 trace_nbd_negotiate_handle_export_name();
439 if (client->optlen >= sizeof(name)) {
440 error_setg(errp, "Bad length received");
441 return -EINVAL;
442 }
443 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) {
444 return -EIO;
445 }
446 name[client->optlen] = '\0';
447 client->optlen = 0;
448
449 trace_nbd_negotiate_handle_export_name_request(name);
450
451 client->exp = nbd_export_find(name);
452 if (!client->exp) {
453 error_setg(errp, "export not found");
454 return -EINVAL;
455 }
456
457 trace_nbd_negotiate_new_style_size_flags(client->exp->size,
458 client->exp->nbdflags | myflags);
459 stq_be_p(buf, client->exp->size);
460 stw_be_p(buf + 8, client->exp->nbdflags | myflags);
461 len = no_zeroes ? 10 : sizeof(buf);
462 ret = nbd_write(client->ioc, buf, len, errp);
463 if (ret < 0) {
464 error_prepend(errp, "write failed: ");
465 return ret;
466 }
467
468 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
469 nbd_export_get(client->exp);
470 nbd_check_meta_export(client);
471
472 return 0;
473 }
474
475 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
476 * The buffer does NOT include the info type prefix.
477 * Return -errno on error, 0 if ready to send more. */
478 static int nbd_negotiate_send_info(NBDClient *client,
479 uint16_t info, uint32_t length, void *buf,
480 Error **errp)
481 {
482 int rc;
483
484 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);
485 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO,
486 sizeof(info) + length, errp);
487 if (rc < 0) {
488 return rc;
489 }
490 info = cpu_to_be16(info);
491 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) {
492 return -EIO;
493 }
494 if (nbd_write(client->ioc, buf, length, errp) < 0) {
495 return -EIO;
496 }
497 return 0;
498 }
499
500 /* nbd_reject_length: Handle any unexpected payload.
501 * @fatal requests that we quit talking to the client, even if we are able
502 * to successfully send an error reply.
503 * Return:
504 * -errno transmission error occurred or @fatal was requested, errp is set
505 * 0 error message successfully sent to client, errp is not set
506 */
507 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp)
508 {
509 int ret;
510
511 assert(client->optlen);
512 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length",
513 nbd_opt_lookup(client->opt));
514 if (fatal && !ret) {
515 error_setg(errp, "option '%s' has unexpected length",
516 nbd_opt_lookup(client->opt));
517 return -EINVAL;
518 }
519 return ret;
520 }
521
522 /* Handle NBD_OPT_INFO and NBD_OPT_GO.
523 * Return -errno on error, 0 if ready for next option, and 1 to move
524 * into transmission phase. */
525 static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,
526 Error **errp)
527 {
528 int rc;
529 char name[NBD_MAX_NAME_SIZE + 1];
530 NBDExport *exp;
531 uint16_t requests;
532 uint16_t request;
533 uint32_t namelen;
534 bool sendname = false;
535 bool blocksize = false;
536 uint32_t sizes[3];
537 char buf[sizeof(uint64_t) + sizeof(uint16_t)];
538 uint32_t check_align = 0;
539
540 /* Client sends:
541 4 bytes: L, name length (can be 0)
542 L bytes: export name
543 2 bytes: N, number of requests (can be 0)
544 N * 2 bytes: N requests
545 */
546 rc = nbd_opt_read_name(client, name, &namelen, errp);
547 if (rc <= 0) {
548 return rc;
549 }
550 trace_nbd_negotiate_handle_export_name_request(name);
551
552 rc = nbd_opt_read(client, &requests, sizeof(requests), errp);
553 if (rc <= 0) {
554 return rc;
555 }
556 requests = be16_to_cpu(requests);
557 trace_nbd_negotiate_handle_info_requests(requests);
558 while (requests--) {
559 rc = nbd_opt_read(client, &request, sizeof(request), errp);
560 if (rc <= 0) {
561 return rc;
562 }
563 request = be16_to_cpu(request);
564 trace_nbd_negotiate_handle_info_request(request,
565 nbd_info_lookup(request));
566 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;
567 * everything else is either a request we don't know or
568 * something we send regardless of request */
569 switch (request) {
570 case NBD_INFO_NAME:
571 sendname = true;
572 break;
573 case NBD_INFO_BLOCK_SIZE:
574 blocksize = true;
575 break;
576 }
577 }
578 if (client->optlen) {
579 return nbd_reject_length(client, false, errp);
580 }
581
582 exp = nbd_export_find(name);
583 if (!exp) {
584 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN,
585 errp, "export '%s' not present",
586 name);
587 }
588
589 /* Don't bother sending NBD_INFO_NAME unless client requested it */
590 if (sendname) {
591 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name,
592 errp);
593 if (rc < 0) {
594 return rc;
595 }
596 }
597
598 /* Send NBD_INFO_DESCRIPTION only if available, regardless of
599 * client request */
600 if (exp->description) {
601 size_t len = strlen(exp->description);
602
603 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION,
604 len, exp->description, errp);
605 if (rc < 0) {
606 return rc;
607 }
608 }
609
610 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size
611 * according to whether the client requested it, and according to
612 * whether this is OPT_INFO or OPT_GO. */
613 /* minimum - 1 for back-compat, or actual if client will obey it. */
614 if (client->opt == NBD_OPT_INFO || blocksize) {
615 check_align = sizes[0] = blk_get_request_alignment(exp->blk);
616 } else {
617 sizes[0] = 1;
618 }
619 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE);
620 /* preferred - Hard-code to 4096 for now.
621 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */
622 sizes[1] = MAX(4096, sizes[0]);
623 /* maximum - At most 32M, but smaller as appropriate. */
624 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE);
625 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]);
626 sizes[0] = cpu_to_be32(sizes[0]);
627 sizes[1] = cpu_to_be32(sizes[1]);
628 sizes[2] = cpu_to_be32(sizes[2]);
629 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE,
630 sizeof(sizes), sizes, errp);
631 if (rc < 0) {
632 return rc;
633 }
634
635 /* Send NBD_INFO_EXPORT always */
636 trace_nbd_negotiate_new_style_size_flags(exp->size,
637 exp->nbdflags | myflags);
638 stq_be_p(buf, exp->size);
639 stw_be_p(buf + 8, exp->nbdflags | myflags);
640 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT,
641 sizeof(buf), buf, errp);
642 if (rc < 0) {
643 return rc;
644 }
645
646 /*
647 * If the client is just asking for NBD_OPT_INFO, but forgot to
648 * request block sizes in a situation that would impact
649 * performance, then return an error. But for NBD_OPT_GO, we
650 * tolerate all clients, regardless of alignments.
651 */
652 if (client->opt == NBD_OPT_INFO && !blocksize &&
653 blk_get_request_alignment(exp->blk) > 1) {
654 return nbd_negotiate_send_rep_err(client,
655 NBD_REP_ERR_BLOCK_SIZE_REQD,
656 errp,
657 "request NBD_INFO_BLOCK_SIZE to "
658 "use this export");
659 }
660
661 /* Final reply */
662 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
663 if (rc < 0) {
664 return rc;
665 }
666
667 if (client->opt == NBD_OPT_GO) {
668 client->exp = exp;
669 client->check_align = check_align;
670 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
671 nbd_export_get(client->exp);
672 nbd_check_meta_export(client);
673 rc = 1;
674 }
675 return rc;
676 }
677
678
679 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
680 * new channel for all further (now-encrypted) communication. */
681 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
682 Error **errp)
683 {
684 QIOChannel *ioc;
685 QIOChannelTLS *tioc;
686 struct NBDTLSHandshakeData data = { 0 };
687
688 assert(client->opt == NBD_OPT_STARTTLS);
689
690 trace_nbd_negotiate_handle_starttls();
691 ioc = client->ioc;
692
693 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) {
694 return NULL;
695 }
696
697 tioc = qio_channel_tls_new_server(ioc,
698 client->tlscreds,
699 client->tlsauthz,
700 errp);
701 if (!tioc) {
702 return NULL;
703 }
704
705 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
706 trace_nbd_negotiate_handle_starttls_handshake();
707 data.loop = g_main_loop_new(g_main_context_default(), FALSE);
708 qio_channel_tls_handshake(tioc,
709 nbd_tls_handshake,
710 &data,
711 NULL,
712 NULL);
713
714 if (!data.complete) {
715 g_main_loop_run(data.loop);
716 }
717 g_main_loop_unref(data.loop);
718 if (data.error) {
719 object_unref(OBJECT(tioc));
720 error_propagate(errp, data.error);
721 return NULL;
722 }
723
724 return QIO_CHANNEL(tioc);
725 }
726
727 /* nbd_negotiate_send_meta_context
728 *
729 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT
730 *
731 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead.
732 */
733 static int nbd_negotiate_send_meta_context(NBDClient *client,
734 const char *context,
735 uint32_t context_id,
736 Error **errp)
737 {
738 NBDOptionReplyMetaContext opt;
739 struct iovec iov[] = {
740 {.iov_base = &opt, .iov_len = sizeof(opt)},
741 {.iov_base = (void *)context, .iov_len = strlen(context)}
742 };
743
744 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
745 context_id = 0;
746 }
747
748 trace_nbd_negotiate_meta_query_reply(context, context_id);
749 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT,
750 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len);
751 stl_be_p(&opt.context_id, context_id);
752
753 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0;
754 }
755
756 /* Read strlen(@pattern) bytes, and set @match to true if they match @pattern.
757 * @match is never set to false.
758 *
759 * Return -errno on I/O error, 0 if option was completely handled by
760 * sending a reply about inconsistent lengths, or 1 on success.
761 *
762 * Note: return code = 1 doesn't mean that we've read exactly @pattern.
763 * It only means that there are no errors.
764 */
765 static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match,
766 Error **errp)
767 {
768 int ret;
769 char *query;
770 size_t len = strlen(pattern);
771
772 assert(len);
773
774 query = g_malloc(len);
775 ret = nbd_opt_read(client, query, len, errp);
776 if (ret <= 0) {
777 g_free(query);
778 return ret;
779 }
780
781 if (strncmp(query, pattern, len) == 0) {
782 trace_nbd_negotiate_meta_query_parse(pattern);
783 *match = true;
784 } else {
785 trace_nbd_negotiate_meta_query_skip("pattern not matched");
786 }
787 g_free(query);
788
789 return 1;
790 }
791
792 /*
793 * Read @len bytes, and set @match to true if they match @pattern, or if @len
794 * is 0 and the client is performing _LIST_. @match is never set to false.
795 *
796 * Return -errno on I/O error, 0 if option was completely handled by
797 * sending a reply about inconsistent lengths, or 1 on success.
798 *
799 * Note: return code = 1 doesn't mean that we've read exactly @pattern.
800 * It only means that there are no errors.
801 */
802 static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
803 uint32_t len, bool *match, Error **errp)
804 {
805 if (len == 0) {
806 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
807 *match = true;
808 }
809 trace_nbd_negotiate_meta_query_parse("empty");
810 return 1;
811 }
812
813 if (len != strlen(pattern)) {
814 trace_nbd_negotiate_meta_query_skip("different lengths");
815 return nbd_opt_skip(client, len, errp);
816 }
817
818 return nbd_meta_pattern(client, pattern, match, errp);
819 }
820
821 /* nbd_meta_base_query
822 *
823 * Handle queries to 'base' namespace. For now, only the base:allocation
824 * context is available. 'len' is the amount of text remaining to be read from
825 * the current name, after the 'base:' portion has been stripped.
826 *
827 * Return -errno on I/O error, 0 if option was completely handled by
828 * sending a reply about inconsistent lengths, or 1 on success.
829 */
830 static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
831 uint32_t len, Error **errp)
832 {
833 return nbd_meta_empty_or_pattern(client, "allocation", len,
834 &meta->base_allocation, errp);
835 }
836
837 /* nbd_meta_bitmap_query
838 *
839 * Handle query to 'qemu:' namespace.
840 * @len is the amount of text remaining to be read from the current name, after
841 * the 'qemu:' portion has been stripped.
842 *
843 * Return -errno on I/O error, 0 if option was completely handled by
844 * sending a reply about inconsistent lengths, or 1 on success. */
845 static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta,
846 uint32_t len, Error **errp)
847 {
848 bool dirty_bitmap = false;
849 size_t dirty_bitmap_len = strlen("dirty-bitmap:");
850 int ret;
851
852 if (!meta->exp->export_bitmap) {
853 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported");
854 return nbd_opt_skip(client, len, errp);
855 }
856
857 if (len == 0) {
858 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
859 meta->bitmap = true;
860 }
861 trace_nbd_negotiate_meta_query_parse("empty");
862 return 1;
863 }
864
865 if (len < dirty_bitmap_len) {
866 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");
867 return nbd_opt_skip(client, len, errp);
868 }
869
870 len -= dirty_bitmap_len;
871 ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp);
872 if (ret <= 0) {
873 return ret;
874 }
875 if (!dirty_bitmap) {
876 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");
877 return nbd_opt_skip(client, len, errp);
878 }
879
880 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:");
881
882 return nbd_meta_empty_or_pattern(
883 client, meta->exp->export_bitmap_context +
884 strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp);
885 }
886
887 /* nbd_negotiate_meta_query
888 *
889 * Parse namespace name and call corresponding function to parse body of the
890 * query.
891 *
892 * The only supported namespace now is 'base'.
893 *
894 * The function aims not wasting time and memory to read long unknown namespace
895 * names.
896 *
897 * Return -errno on I/O error, 0 if option was completely handled by
898 * sending a reply about inconsistent lengths, or 1 on success. */
899 static int nbd_negotiate_meta_query(NBDClient *client,
900 NBDExportMetaContexts *meta, Error **errp)
901 {
902 /*
903 * Both 'qemu' and 'base' namespaces have length = 5 including a
904 * colon. If another length namespace is later introduced, this
905 * should certainly be refactored.
906 */
907 int ret;
908 size_t ns_len = 5;
909 char ns[5];
910 uint32_t len;
911
912 ret = nbd_opt_read(client, &len, sizeof(len), errp);
913 if (ret <= 0) {
914 return ret;
915 }
916 len = cpu_to_be32(len);
917
918 if (len < ns_len) {
919 trace_nbd_negotiate_meta_query_skip("length too short");
920 return nbd_opt_skip(client, len, errp);
921 }
922
923 len -= ns_len;
924 ret = nbd_opt_read(client, ns, ns_len, errp);
925 if (ret <= 0) {
926 return ret;
927 }
928
929 if (!strncmp(ns, "base:", ns_len)) {
930 trace_nbd_negotiate_meta_query_parse("base:");
931 return nbd_meta_base_query(client, meta, len, errp);
932 } else if (!strncmp(ns, "qemu:", ns_len)) {
933 trace_nbd_negotiate_meta_query_parse("qemu:");
934 return nbd_meta_qemu_query(client, meta, len, errp);
935 }
936
937 trace_nbd_negotiate_meta_query_skip("unknown namespace");
938 return nbd_opt_skip(client, len, errp);
939 }
940
941 /* nbd_negotiate_meta_queries
942 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT
943 *
944 * Return -errno on I/O error, or 0 if option was completely handled. */
945 static int nbd_negotiate_meta_queries(NBDClient *client,
946 NBDExportMetaContexts *meta, Error **errp)
947 {
948 int ret;
949 char export_name[NBD_MAX_NAME_SIZE + 1];
950 NBDExportMetaContexts local_meta;
951 uint32_t nb_queries;
952 int i;
953
954 if (!client->structured_reply) {
955 return nbd_opt_invalid(client, errp,
956 "request option '%s' when structured reply "
957 "is not negotiated",
958 nbd_opt_lookup(client->opt));
959 }
960
961 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
962 /* Only change the caller's meta on SET. */
963 meta = &local_meta;
964 }
965
966 memset(meta, 0, sizeof(*meta));
967
968 ret = nbd_opt_read_name(client, export_name, NULL, errp);
969 if (ret <= 0) {
970 return ret;
971 }
972
973 meta->exp = nbd_export_find(export_name);
974 if (meta->exp == NULL) {
975 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp,
976 "export '%s' not present", export_name);
977 }
978
979 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp);
980 if (ret <= 0) {
981 return ret;
982 }
983 nb_queries = cpu_to_be32(nb_queries);
984 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt),
985 export_name, nb_queries);
986
987 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) {
988 /* enable all known contexts */
989 meta->base_allocation = true;
990 meta->bitmap = !!meta->exp->export_bitmap;
991 } else {
992 for (i = 0; i < nb_queries; ++i) {
993 ret = nbd_negotiate_meta_query(client, meta, errp);
994 if (ret <= 0) {
995 return ret;
996 }
997 }
998 }
999
1000 if (meta->base_allocation) {
1001 ret = nbd_negotiate_send_meta_context(client, "base:allocation",
1002 NBD_META_ID_BASE_ALLOCATION,
1003 errp);
1004 if (ret < 0) {
1005 return ret;
1006 }
1007 }
1008
1009 if (meta->bitmap) {
1010 ret = nbd_negotiate_send_meta_context(client,
1011 meta->exp->export_bitmap_context,
1012 NBD_META_ID_DIRTY_BITMAP,
1013 errp);
1014 if (ret < 0) {
1015 return ret;
1016 }
1017 }
1018
1019 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1020 if (ret == 0) {
1021 meta->valid = true;
1022 }
1023
1024 return ret;
1025 }
1026
1027 /* nbd_negotiate_options
1028 * Process all NBD_OPT_* client option commands, during fixed newstyle
1029 * negotiation.
1030 * Return:
1031 * -errno on error, errp is set
1032 * 0 on successful negotiation, errp is not set
1033 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
1034 * errp is not set
1035 */
1036 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
1037 Error **errp)
1038 {
1039 uint32_t flags;
1040 bool fixedNewstyle = false;
1041 bool no_zeroes = false;
1042
1043 /* Client sends:
1044 [ 0 .. 3] client flags
1045
1046 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO:
1047 [ 0 .. 7] NBD_OPTS_MAGIC
1048 [ 8 .. 11] NBD option
1049 [12 .. 15] Data length
1050 ... Rest of request
1051
1052 [ 0 .. 7] NBD_OPTS_MAGIC
1053 [ 8 .. 11] Second NBD option
1054 [12 .. 15] Data length
1055 ... Rest of request
1056 */
1057
1058 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) {
1059 return -EIO;
1060 }
1061 trace_nbd_negotiate_options_flags(flags);
1062 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
1063 fixedNewstyle = true;
1064 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
1065 }
1066 if (flags & NBD_FLAG_C_NO_ZEROES) {
1067 no_zeroes = true;
1068 flags &= ~NBD_FLAG_C_NO_ZEROES;
1069 }
1070 if (flags != 0) {
1071 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);
1072 return -EINVAL;
1073 }
1074
1075 while (1) {
1076 int ret;
1077 uint32_t option, length;
1078 uint64_t magic;
1079
1080 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) {
1081 return -EINVAL;
1082 }
1083 trace_nbd_negotiate_options_check_magic(magic);
1084 if (magic != NBD_OPTS_MAGIC) {
1085 error_setg(errp, "Bad magic received");
1086 return -EINVAL;
1087 }
1088
1089 if (nbd_read32(client->ioc, &option, "option", errp) < 0) {
1090 return -EINVAL;
1091 }
1092 client->opt = option;
1093
1094 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) {
1095 return -EINVAL;
1096 }
1097 assert(!client->optlen);
1098 client->optlen = length;
1099
1100 if (length > NBD_MAX_BUFFER_SIZE) {
1101 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
1102 length, NBD_MAX_BUFFER_SIZE);
1103 return -EINVAL;
1104 }
1105
1106 trace_nbd_negotiate_options_check_option(option,
1107 nbd_opt_lookup(option));
1108 if (client->tlscreds &&
1109 client->ioc == (QIOChannel *)client->sioc) {
1110 QIOChannel *tioc;
1111 if (!fixedNewstyle) {
1112 error_setg(errp, "Unsupported option 0x%" PRIx32, option);
1113 return -EINVAL;
1114 }
1115 switch (option) {
1116 case NBD_OPT_STARTTLS:
1117 if (length) {
1118 /* Unconditionally drop the connection if the client
1119 * can't start a TLS negotiation correctly */
1120 return nbd_reject_length(client, true, errp);
1121 }
1122 tioc = nbd_negotiate_handle_starttls(client, errp);
1123 if (!tioc) {
1124 return -EIO;
1125 }
1126 ret = 0;
1127 object_unref(OBJECT(client->ioc));
1128 client->ioc = QIO_CHANNEL(tioc);
1129 break;
1130
1131 case NBD_OPT_EXPORT_NAME:
1132 /* No way to return an error to client, so drop connection */
1133 error_setg(errp, "Option 0x%x not permitted before TLS",
1134 option);
1135 return -EINVAL;
1136
1137 default:
1138 /* Let the client keep trying, unless they asked to
1139 * quit. Always try to give an error back to the
1140 * client; but when replying to OPT_ABORT, be aware
1141 * that the client may hang up before receiving the
1142 * error, in which case we are fine ignoring the
1143 * resulting EPIPE. */
1144 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD,
1145 option == NBD_OPT_ABORT ? NULL : errp,
1146 "Option 0x%" PRIx32
1147 " not permitted before TLS", option);
1148 if (option == NBD_OPT_ABORT) {
1149 return 1;
1150 }
1151 break;
1152 }
1153 } else if (fixedNewstyle) {
1154 switch (option) {
1155 case NBD_OPT_LIST:
1156 if (length) {
1157 ret = nbd_reject_length(client, false, errp);
1158 } else {
1159 ret = nbd_negotiate_handle_list(client, errp);
1160 }
1161 break;
1162
1163 case NBD_OPT_ABORT:
1164 /* NBD spec says we must try to reply before
1165 * disconnecting, but that we must also tolerate
1166 * guests that don't wait for our reply. */
1167 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL);
1168 return 1;
1169
1170 case NBD_OPT_EXPORT_NAME:
1171 return nbd_negotiate_handle_export_name(client,
1172 myflags, no_zeroes,
1173 errp);
1174
1175 case NBD_OPT_INFO:
1176 case NBD_OPT_GO:
1177 ret = nbd_negotiate_handle_info(client, myflags, errp);
1178 if (ret == 1) {
1179 assert(option == NBD_OPT_GO);
1180 return 0;
1181 }
1182 break;
1183
1184 case NBD_OPT_STARTTLS:
1185 if (length) {
1186 ret = nbd_reject_length(client, false, errp);
1187 } else if (client->tlscreds) {
1188 ret = nbd_negotiate_send_rep_err(client,
1189 NBD_REP_ERR_INVALID, errp,
1190 "TLS already enabled");
1191 } else {
1192 ret = nbd_negotiate_send_rep_err(client,
1193 NBD_REP_ERR_POLICY, errp,
1194 "TLS not configured");
1195 }
1196 break;
1197
1198 case NBD_OPT_STRUCTURED_REPLY:
1199 if (length) {
1200 ret = nbd_reject_length(client, false, errp);
1201 } else if (client->structured_reply) {
1202 ret = nbd_negotiate_send_rep_err(
1203 client, NBD_REP_ERR_INVALID, errp,
1204 "structured reply already negotiated");
1205 } else {
1206 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1207 client->structured_reply = true;
1208 myflags |= NBD_FLAG_SEND_DF;
1209 }
1210 break;
1211
1212 case NBD_OPT_LIST_META_CONTEXT:
1213 case NBD_OPT_SET_META_CONTEXT:
1214 ret = nbd_negotiate_meta_queries(client, &client->export_meta,
1215 errp);
1216 break;
1217
1218 default:
1219 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp,
1220 "Unsupported option %" PRIu32 " (%s)",
1221 option, nbd_opt_lookup(option));
1222 break;
1223 }
1224 } else {
1225 /*
1226 * If broken new-style we should drop the connection
1227 * for anything except NBD_OPT_EXPORT_NAME
1228 */
1229 switch (option) {
1230 case NBD_OPT_EXPORT_NAME:
1231 return nbd_negotiate_handle_export_name(client,
1232 myflags, no_zeroes,
1233 errp);
1234
1235 default:
1236 error_setg(errp, "Unsupported option %" PRIu32 " (%s)",
1237 option, nbd_opt_lookup(option));
1238 return -EINVAL;
1239 }
1240 }
1241 if (ret < 0) {
1242 return ret;
1243 }
1244 }
1245 }
1246
1247 /* nbd_negotiate
1248 * Return:
1249 * -errno on error, errp is set
1250 * 0 on successful negotiation, errp is not set
1251 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
1252 * errp is not set
1253 */
1254 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
1255 {
1256 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";
1257 int ret;
1258 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
1259 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA |
1260 NBD_FLAG_SEND_WRITE_ZEROES | NBD_FLAG_SEND_CACHE);
1261
1262 /* Old style negotiation header, no room for options
1263 [ 0 .. 7] passwd ("NBDMAGIC")
1264 [ 8 .. 15] magic (NBD_CLIENT_MAGIC)
1265 [16 .. 23] size
1266 [24 .. 27] export flags (zero-extended)
1267 [28 .. 151] reserved (0)
1268
1269 New style negotiation header, client can send options
1270 [ 0 .. 7] passwd ("NBDMAGIC")
1271 [ 8 .. 15] magic (NBD_OPTS_MAGIC)
1272 [16 .. 17] server flags (0)
1273 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO....
1274 */
1275
1276 qio_channel_set_blocking(client->ioc, false, NULL);
1277
1278 trace_nbd_negotiate_begin();
1279 memcpy(buf, "NBDMAGIC", 8);
1280
1281 stq_be_p(buf + 8, NBD_OPTS_MAGIC);
1282 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);
1283
1284 if (nbd_write(client->ioc, buf, 18, errp) < 0) {
1285 error_prepend(errp, "write failed: ");
1286 return -EINVAL;
1287 }
1288 ret = nbd_negotiate_options(client, myflags, errp);
1289 if (ret != 0) {
1290 if (ret < 0) {
1291 error_prepend(errp, "option negotiation failed: ");
1292 }
1293 return ret;
1294 }
1295
1296 assert(!client->optlen);
1297 trace_nbd_negotiate_success();
1298
1299 return 0;
1300 }
1301
1302 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request,
1303 Error **errp)
1304 {
1305 uint8_t buf[NBD_REQUEST_SIZE];
1306 uint32_t magic;
1307 int ret;
1308
1309 ret = nbd_read(ioc, buf, sizeof(buf), "request", errp);
1310 if (ret < 0) {
1311 return ret;
1312 }
1313
1314 /* Request
1315 [ 0 .. 3] magic (NBD_REQUEST_MAGIC)
1316 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...)
1317 [ 6 .. 7] type (NBD_CMD_READ, ...)
1318 [ 8 .. 15] handle
1319 [16 .. 23] from
1320 [24 .. 27] len
1321 */
1322
1323 magic = ldl_be_p(buf);
1324 request->flags = lduw_be_p(buf + 4);
1325 request->type = lduw_be_p(buf + 6);
1326 request->handle = ldq_be_p(buf + 8);
1327 request->from = ldq_be_p(buf + 16);
1328 request->len = ldl_be_p(buf + 24);
1329
1330 trace_nbd_receive_request(magic, request->flags, request->type,
1331 request->from, request->len);
1332
1333 if (magic != NBD_REQUEST_MAGIC) {
1334 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic);
1335 return -EINVAL;
1336 }
1337 return 0;
1338 }
1339
1340 #define MAX_NBD_REQUESTS 16
1341
1342 void nbd_client_get(NBDClient *client)
1343 {
1344 client->refcount++;
1345 }
1346
1347 void nbd_client_put(NBDClient *client)
1348 {
1349 if (--client->refcount == 0) {
1350 /* The last reference should be dropped by client->close,
1351 * which is called by client_close.
1352 */
1353 assert(client->closing);
1354
1355 qio_channel_detach_aio_context(client->ioc);
1356 object_unref(OBJECT(client->sioc));
1357 object_unref(OBJECT(client->ioc));
1358 if (client->tlscreds) {
1359 object_unref(OBJECT(client->tlscreds));
1360 }
1361 g_free(client->tlsauthz);
1362 if (client->exp) {
1363 QTAILQ_REMOVE(&client->exp->clients, client, next);
1364 nbd_export_put(client->exp);
1365 }
1366 g_free(client);
1367 }
1368 }
1369
1370 static void client_close(NBDClient *client, bool negotiated)
1371 {
1372 if (client->closing) {
1373 return;
1374 }
1375
1376 client->closing = true;
1377
1378 /* Force requests to finish. They will drop their own references,
1379 * then we'll close the socket and free the NBDClient.
1380 */
1381 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
1382 NULL);
1383
1384 /* Also tell the client, so that they release their reference. */
1385 if (client->close_fn) {
1386 client->close_fn(client, negotiated);
1387 }
1388 }
1389
1390 static NBDRequestData *nbd_request_get(NBDClient *client)
1391 {
1392 NBDRequestData *req;
1393
1394 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
1395 client->nb_requests++;
1396
1397 req = g_new0(NBDRequestData, 1);
1398 nbd_client_get(client);
1399 req->client = client;
1400 return req;
1401 }
1402
1403 static void nbd_request_put(NBDRequestData *req)
1404 {
1405 NBDClient *client = req->client;
1406
1407 if (req->data) {
1408 qemu_vfree(req->data);
1409 }
1410 g_free(req);
1411
1412 client->nb_requests--;
1413 nbd_client_receive_next_request(client);
1414
1415 nbd_client_put(client);
1416 }
1417
1418 static void blk_aio_attached(AioContext *ctx, void *opaque)
1419 {
1420 NBDExport *exp = opaque;
1421 NBDClient *client;
1422
1423 trace_nbd_blk_aio_attached(exp->name, ctx);
1424
1425 exp->ctx = ctx;
1426
1427 QTAILQ_FOREACH(client, &exp->clients, next) {
1428 qio_channel_attach_aio_context(client->ioc, ctx);
1429 if (client->recv_coroutine) {
1430 aio_co_schedule(ctx, client->recv_coroutine);
1431 }
1432 if (client->send_coroutine) {
1433 aio_co_schedule(ctx, client->send_coroutine);
1434 }
1435 }
1436 }
1437
1438 static void blk_aio_detach(void *opaque)
1439 {
1440 NBDExport *exp = opaque;
1441 NBDClient *client;
1442
1443 trace_nbd_blk_aio_detach(exp->name, exp->ctx);
1444
1445 QTAILQ_FOREACH(client, &exp->clients, next) {
1446 qio_channel_detach_aio_context(client->ioc);
1447 }
1448
1449 exp->ctx = NULL;
1450 }
1451
1452 static void nbd_eject_notifier(Notifier *n, void *data)
1453 {
1454 NBDExport *exp = container_of(n, NBDExport, eject_notifier);
1455 nbd_export_close(exp);
1456 }
1457
1458 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
1459 uint64_t size, const char *name, const char *desc,
1460 const char *bitmap, uint16_t nbdflags,
1461 void (*close)(NBDExport *), bool writethrough,
1462 BlockBackend *on_eject_blk, Error **errp)
1463 {
1464 AioContext *ctx;
1465 BlockBackend *blk;
1466 NBDExport *exp = g_new0(NBDExport, 1);
1467 uint64_t perm;
1468 int ret;
1469
1470 /*
1471 * NBD exports are used for non-shared storage migration. Make sure
1472 * that BDRV_O_INACTIVE is cleared and the image is ready for write
1473 * access since the export could be available before migration handover.
1474 */
1475 assert(name);
1476 ctx = bdrv_get_aio_context(bs);
1477 aio_context_acquire(ctx);
1478 bdrv_invalidate_cache(bs, NULL);
1479 aio_context_release(ctx);
1480
1481 /* Don't allow resize while the NBD server is running, otherwise we don't
1482 * care what happens with the node. */
1483 perm = BLK_PERM_CONSISTENT_READ;
1484 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) {
1485 perm |= BLK_PERM_WRITE;
1486 }
1487 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
1488 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD);
1489 ret = blk_insert_bs(blk, bs, errp);
1490 if (ret < 0) {
1491 goto fail;
1492 }
1493 blk_set_enable_write_cache(blk, !writethrough);
1494
1495 exp->refcount = 1;
1496 QTAILQ_INIT(&exp->clients);
1497 exp->blk = blk;
1498 assert(dev_offset <= INT64_MAX);
1499 exp->dev_offset = dev_offset;
1500 exp->name = g_strdup(name);
1501 exp->description = g_strdup(desc);
1502 exp->nbdflags = nbdflags;
1503 assert(size <= INT64_MAX - dev_offset);
1504 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE);
1505
1506 if (bitmap) {
1507 BdrvDirtyBitmap *bm = NULL;
1508
1509 while (true) {
1510 bm = bdrv_find_dirty_bitmap(bs, bitmap);
1511 if (bm != NULL || bs->backing == NULL) {
1512 break;
1513 }
1514
1515 bs = bs->backing->bs;
1516 }
1517
1518 if (bm == NULL) {
1519 error_setg(errp, "Bitmap '%s' is not found", bitmap);
1520 goto fail;
1521 }
1522
1523 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) {
1524 goto fail;
1525 }
1526
1527 if ((nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) &&
1528 bdrv_dirty_bitmap_enabled(bm)) {
1529 error_setg(errp,
1530 "Enabled bitmap '%s' incompatible with readonly export",
1531 bitmap);
1532 goto fail;
1533 }
1534
1535 bdrv_dirty_bitmap_set_busy(bm, true);
1536 exp->export_bitmap = bm;
1537 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s",
1538 bitmap);
1539 }
1540
1541 exp->close = close;
1542 exp->ctx = blk_get_aio_context(blk);
1543 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
1544
1545 if (on_eject_blk) {
1546 blk_ref(on_eject_blk);
1547 exp->eject_notifier_blk = on_eject_blk;
1548 exp->eject_notifier.notify = nbd_eject_notifier;
1549 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
1550 }
1551 QTAILQ_INSERT_TAIL(&exports, exp, next);
1552 nbd_export_get(exp);
1553 return exp;
1554
1555 fail:
1556 blk_unref(blk);
1557 g_free(exp->name);
1558 g_free(exp->description);
1559 g_free(exp);
1560 return NULL;
1561 }
1562
1563 NBDExport *nbd_export_find(const char *name)
1564 {
1565 NBDExport *exp;
1566 QTAILQ_FOREACH(exp, &exports, next) {
1567 if (strcmp(name, exp->name) == 0) {
1568 return exp;
1569 }
1570 }
1571
1572 return NULL;
1573 }
1574
1575 void nbd_export_close(NBDExport *exp)
1576 {
1577 NBDClient *client, *next;
1578
1579 nbd_export_get(exp);
1580 /*
1581 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a
1582 * close mode that stops advertising the export to new clients but
1583 * still permits existing clients to run to completion? Because of
1584 * that possibility, nbd_export_close() can be called more than
1585 * once on an export.
1586 */
1587 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
1588 client_close(client, true);
1589 }
1590 if (exp->name) {
1591 nbd_export_put(exp);
1592 g_free(exp->name);
1593 exp->name = NULL;
1594 QTAILQ_REMOVE(&exports, exp, next);
1595 }
1596 g_free(exp->description);
1597 exp->description = NULL;
1598 nbd_export_put(exp);
1599 }
1600
1601 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp)
1602 {
1603 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) {
1604 nbd_export_close(exp);
1605 return;
1606 }
1607
1608 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE);
1609
1610 error_setg(errp, "export '%s' still in use", exp->name);
1611 error_append_hint(errp, "Use mode='hard' to force client disconnect\n");
1612 }
1613
1614 void nbd_export_get(NBDExport *exp)
1615 {
1616 assert(exp->refcount > 0);
1617 exp->refcount++;
1618 }
1619
1620 void nbd_export_put(NBDExport *exp)
1621 {
1622 assert(exp->refcount > 0);
1623 if (exp->refcount == 1) {
1624 nbd_export_close(exp);
1625 }
1626
1627 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen
1628 * if someone calls nbd_export_put() on named export not through
1629 * nbd_export_set_name() when refcount is 1. So, let's assert that
1630 * it is > 0.
1631 */
1632 assert(exp->refcount > 0);
1633 if (--exp->refcount == 0) {
1634 assert(exp->name == NULL);
1635 assert(exp->description == NULL);
1636
1637 if (exp->close) {
1638 exp->close(exp);
1639 }
1640
1641 if (exp->blk) {
1642 if (exp->eject_notifier_blk) {
1643 notifier_remove(&exp->eject_notifier);
1644 blk_unref(exp->eject_notifier_blk);
1645 }
1646 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
1647 blk_aio_detach, exp);
1648 blk_unref(exp->blk);
1649 exp->blk = NULL;
1650 }
1651
1652 if (exp->export_bitmap) {
1653 bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false);
1654 g_free(exp->export_bitmap_context);
1655 }
1656
1657 g_free(exp);
1658 }
1659 }
1660
1661 BlockBackend *nbd_export_get_blockdev(NBDExport *exp)
1662 {
1663 return exp->blk;
1664 }
1665
1666 void nbd_export_close_all(void)
1667 {
1668 NBDExport *exp, *next;
1669
1670 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {
1671 nbd_export_close(exp);
1672 }
1673 }
1674
1675 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov,
1676 unsigned niov, Error **errp)
1677 {
1678 int ret;
1679
1680 g_assert(qemu_in_coroutine());
1681 qemu_co_mutex_lock(&client->send_lock);
1682 client->send_coroutine = qemu_coroutine_self();
1683
1684 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0;
1685
1686 client->send_coroutine = NULL;
1687 qemu_co_mutex_unlock(&client->send_lock);
1688
1689 return ret;
1690 }
1691
1692 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,
1693 uint64_t handle)
1694 {
1695 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);
1696 stl_be_p(&reply->error, error);
1697 stq_be_p(&reply->handle, handle);
1698 }
1699
1700 static int nbd_co_send_simple_reply(NBDClient *client,
1701 uint64_t handle,
1702 uint32_t error,
1703 void *data,
1704 size_t len,
1705 Error **errp)
1706 {
1707 NBDSimpleReply reply;
1708 int nbd_err = system_errno_to_nbd_errno(error);
1709 struct iovec iov[] = {
1710 {.iov_base = &reply, .iov_len = sizeof(reply)},
1711 {.iov_base = data, .iov_len = len}
1712 };
1713
1714 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err),
1715 len);
1716 set_be_simple_reply(&reply, nbd_err, handle);
1717
1718 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp);
1719 }
1720
1721 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags,
1722 uint16_t type, uint64_t handle, uint32_t length)
1723 {
1724 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC);
1725 stw_be_p(&chunk->flags, flags);
1726 stw_be_p(&chunk->type, type);
1727 stq_be_p(&chunk->handle, handle);
1728 stl_be_p(&chunk->length, length);
1729 }
1730
1731 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client,
1732 uint64_t handle,
1733 Error **errp)
1734 {
1735 NBDStructuredReplyChunk chunk;
1736 struct iovec iov[] = {
1737 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1738 };
1739
1740 trace_nbd_co_send_structured_done(handle);
1741 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0);
1742
1743 return nbd_co_send_iov(client, iov, 1, errp);
1744 }
1745
1746 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client,
1747 uint64_t handle,
1748 uint64_t offset,
1749 void *data,
1750 size_t size,
1751 bool final,
1752 Error **errp)
1753 {
1754 NBDStructuredReadData chunk;
1755 struct iovec iov[] = {
1756 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1757 {.iov_base = data, .iov_len = size}
1758 };
1759
1760 assert(size);
1761 trace_nbd_co_send_structured_read(handle, offset, data, size);
1762 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
1763 NBD_REPLY_TYPE_OFFSET_DATA, handle,
1764 sizeof(chunk) - sizeof(chunk.h) + size);
1765 stq_be_p(&chunk.offset, offset);
1766
1767 return nbd_co_send_iov(client, iov, 2, errp);
1768 }
1769
1770 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client,
1771 uint64_t handle,
1772 uint32_t error,
1773 const char *msg,
1774 Error **errp)
1775 {
1776 NBDStructuredError chunk;
1777 int nbd_err = system_errno_to_nbd_errno(error);
1778 struct iovec iov[] = {
1779 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1780 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0},
1781 };
1782
1783 assert(nbd_err);
1784 trace_nbd_co_send_structured_error(handle, nbd_err,
1785 nbd_err_lookup(nbd_err), msg ? msg : "");
1786 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle,
1787 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
1788 stl_be_p(&chunk.error, nbd_err);
1789 stw_be_p(&chunk.message_length, iov[1].iov_len);
1790
1791 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp);
1792 }
1793
1794 /* Do a sparse read and send the structured reply to the client.
1795 * Returns -errno if sending fails. bdrv_block_status_above() failure is
1796 * reported to the client, at which point this function succeeds.
1797 */
1798 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
1799 uint64_t handle,
1800 uint64_t offset,
1801 uint8_t *data,
1802 size_t size,
1803 Error **errp)
1804 {
1805 int ret = 0;
1806 NBDExport *exp = client->exp;
1807 size_t progress = 0;
1808
1809 while (progress < size) {
1810 int64_t pnum;
1811 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL,
1812 offset + progress,
1813 size - progress, &pnum, NULL,
1814 NULL);
1815 bool final;
1816
1817 if (status < 0) {
1818 char *msg = g_strdup_printf("unable to check for holes: %s",
1819 strerror(-status));
1820
1821 ret = nbd_co_send_structured_error(client, handle, -status, msg,
1822 errp);
1823 g_free(msg);
1824 return ret;
1825 }
1826 assert(pnum && pnum <= size - progress);
1827 final = progress + pnum == size;
1828 if (status & BDRV_BLOCK_ZERO) {
1829 NBDStructuredReadHole chunk;
1830 struct iovec iov[] = {
1831 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1832 };
1833
1834 trace_nbd_co_send_structured_read_hole(handle, offset + progress,
1835 pnum);
1836 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
1837 NBD_REPLY_TYPE_OFFSET_HOLE,
1838 handle, sizeof(chunk) - sizeof(chunk.h));
1839 stq_be_p(&chunk.offset, offset + progress);
1840 stl_be_p(&chunk.length, pnum);
1841 ret = nbd_co_send_iov(client, iov, 1, errp);
1842 } else {
1843 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset,
1844 data + progress, pnum);
1845 if (ret < 0) {
1846 error_setg_errno(errp, -ret, "reading from file failed");
1847 break;
1848 }
1849 ret = nbd_co_send_structured_read(client, handle, offset + progress,
1850 data + progress, pnum, final,
1851 errp);
1852 }
1853
1854 if (ret < 0) {
1855 break;
1856 }
1857 progress += pnum;
1858 }
1859 return ret;
1860 }
1861
1862 /*
1863 * Populate @extents from block status. Update @bytes to be the actual
1864 * length encoded (which may be smaller than the original), and update
1865 * @nb_extents to the number of extents used.
1866 *
1867 * Returns zero on success and -errno on bdrv_block_status_above failure.
1868 */
1869 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset,
1870 uint64_t *bytes, NBDExtent *extents,
1871 unsigned int *nb_extents)
1872 {
1873 uint64_t remaining_bytes = *bytes;
1874 NBDExtent *extent = extents, *extents_end = extents + *nb_extents;
1875 bool first_extent = true;
1876
1877 assert(*nb_extents);
1878 while (remaining_bytes) {
1879 uint32_t flags;
1880 int64_t num;
1881 int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes,
1882 &num, NULL, NULL);
1883
1884 if (ret < 0) {
1885 return ret;
1886 }
1887
1888 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) |
1889 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0);
1890
1891 if (first_extent) {
1892 extent->flags = flags;
1893 extent->length = num;
1894 first_extent = false;
1895 } else if (flags == extent->flags) {
1896 /* extend current extent */
1897 extent->length += num;
1898 } else {
1899 if (extent + 1 == extents_end) {
1900 break;
1901 }
1902
1903 /* start new extent */
1904 extent++;
1905 extent->flags = flags;
1906 extent->length = num;
1907 }
1908 offset += num;
1909 remaining_bytes -= num;
1910 }
1911
1912 extents_end = extent + 1;
1913
1914 for (extent = extents; extent < extents_end; extent++) {
1915 extent->flags = cpu_to_be32(extent->flags);
1916 extent->length = cpu_to_be32(extent->length);
1917 }
1918
1919 *bytes -= remaining_bytes;
1920 *nb_extents = extents_end - extents;
1921
1922 return 0;
1923 }
1924
1925 /* nbd_co_send_extents
1926 *
1927 * @length is only for tracing purposes (and may be smaller or larger
1928 * than the client's original request). @last controls whether
1929 * NBD_REPLY_FLAG_DONE is sent. @extents should already be in
1930 * big-endian format.
1931 */
1932 static int nbd_co_send_extents(NBDClient *client, uint64_t handle,
1933 NBDExtent *extents, unsigned int nb_extents,
1934 uint64_t length, bool last,
1935 uint32_t context_id, Error **errp)
1936 {
1937 NBDStructuredMeta chunk;
1938
1939 struct iovec iov[] = {
1940 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1941 {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])}
1942 };
1943
1944 trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last);
1945 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0,
1946 NBD_REPLY_TYPE_BLOCK_STATUS,
1947 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
1948 stl_be_p(&chunk.context_id, context_id);
1949
1950 return nbd_co_send_iov(client, iov, 2, errp);
1951 }
1952
1953 /* Get block status from the exported device and send it to the client */
1954 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle,
1955 BlockDriverState *bs, uint64_t offset,
1956 uint32_t length, bool dont_fragment,
1957 bool last, uint32_t context_id,
1958 Error **errp)
1959 {
1960 int ret;
1961 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS;
1962 NBDExtent *extents = g_new(NBDExtent, nb_extents);
1963 uint64_t final_length = length;
1964
1965 ret = blockstatus_to_extents(bs, offset, &final_length, extents,
1966 &nb_extents);
1967 if (ret < 0) {
1968 g_free(extents);
1969 return nbd_co_send_structured_error(
1970 client, handle, -ret, "can't get block status", errp);
1971 }
1972
1973 ret = nbd_co_send_extents(client, handle, extents, nb_extents,
1974 final_length, last, context_id, errp);
1975
1976 g_free(extents);
1977
1978 return ret;
1979 }
1980
1981 /*
1982 * Populate @extents from a dirty bitmap. Unless @dont_fragment, the
1983 * final extent may exceed the original @length. Store in @length the
1984 * byte length encoded (which may be smaller or larger than the
1985 * original), and return the number of extents used.
1986 */
1987 static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset,
1988 uint64_t *length, NBDExtent *extents,
1989 unsigned int nb_extents,
1990 bool dont_fragment)
1991 {
1992 uint64_t begin = offset, end = offset;
1993 uint64_t overall_end = offset + *length;
1994 unsigned int i = 0;
1995 BdrvDirtyBitmapIter *it;
1996 bool dirty;
1997
1998 bdrv_dirty_bitmap_lock(bitmap);
1999
2000 it = bdrv_dirty_iter_new(bitmap);
2001 dirty = bdrv_get_dirty_locked(NULL, bitmap, offset);
2002
2003 assert(begin < overall_end && nb_extents);
2004 while (begin < overall_end && i < nb_extents) {
2005 bool next_dirty = !dirty;
2006
2007 if (dirty) {
2008 end = bdrv_dirty_bitmap_next_zero(bitmap, begin, UINT64_MAX);
2009 } else {
2010 bdrv_set_dirty_iter(it, begin);
2011 end = bdrv_dirty_iter_next(it);
2012 }
2013 if (end == -1 || end - begin > UINT32_MAX) {
2014 /* Cap to an aligned value < 4G beyond begin. */
2015 end = MIN(bdrv_dirty_bitmap_size(bitmap),
2016 begin + UINT32_MAX + 1 -
2017 bdrv_dirty_bitmap_granularity(bitmap));
2018 next_dirty = dirty;
2019 }
2020 if (dont_fragment && end > overall_end) {
2021 end = overall_end;
2022 }
2023
2024 extents[i].length = cpu_to_be32(end - begin);
2025 extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0);
2026 i++;
2027 begin = end;
2028 dirty = next_dirty;
2029 }
2030
2031 bdrv_dirty_iter_free(it);
2032
2033 bdrv_dirty_bitmap_unlock(bitmap);
2034
2035 assert(offset < end);
2036 *length = end - offset;
2037 return i;
2038 }
2039
2040 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle,
2041 BdrvDirtyBitmap *bitmap, uint64_t offset,
2042 uint32_t length, bool dont_fragment, bool last,
2043 uint32_t context_id, Error **errp)
2044 {
2045 int ret;
2046 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS;
2047 NBDExtent *extents = g_new(NBDExtent, nb_extents);
2048 uint64_t final_length = length;
2049
2050 nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents,
2051 nb_extents, dont_fragment);
2052
2053 ret = nbd_co_send_extents(client, handle, extents, nb_extents,
2054 final_length, last, context_id, errp);
2055
2056 g_free(extents);
2057
2058 return ret;
2059 }
2060
2061 /* nbd_co_receive_request
2062 * Collect a client request. Return 0 if request looks valid, -EIO to drop
2063 * connection right away, and any other negative value to report an error to
2064 * the client (although the caller may still need to disconnect after reporting
2065 * the error).
2066 */
2067 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,
2068 Error **errp)
2069 {
2070 NBDClient *client = req->client;
2071 int valid_flags;
2072
2073 g_assert(qemu_in_coroutine());
2074 assert(client->recv_coroutine == qemu_coroutine_self());
2075 if (nbd_receive_request(client->ioc, request, errp) < 0) {
2076 return -EIO;
2077 }
2078
2079 trace_nbd_co_receive_request_decode_type(request->handle, request->type,
2080 nbd_cmd_lookup(request->type));
2081
2082 if (request->type != NBD_CMD_WRITE) {
2083 /* No payload, we are ready to read the next request. */
2084 req->complete = true;
2085 }
2086
2087 if (request->type == NBD_CMD_DISC) {
2088 /* Special case: we're going to disconnect without a reply,
2089 * whether or not flags, from, or len are bogus */
2090 return -EIO;
2091 }
2092
2093 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE ||
2094 request->type == NBD_CMD_CACHE)
2095 {
2096 if (request->len > NBD_MAX_BUFFER_SIZE) {
2097 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
2098 request->len, NBD_MAX_BUFFER_SIZE);
2099 return -EINVAL;
2100 }
2101
2102 req->data = blk_try_blockalign(client->exp->blk, request->len);
2103 if (req->data == NULL) {
2104 error_setg(errp, "No memory");
2105 return -ENOMEM;
2106 }
2107 }
2108 if (request->type == NBD_CMD_WRITE) {
2109 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data",
2110 errp) < 0)
2111 {
2112 return -EIO;
2113 }
2114 req->complete = true;
2115
2116 trace_nbd_co_receive_request_payload_received(request->handle,
2117 request->len);
2118 }
2119
2120 /* Sanity checks. */
2121 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY &&
2122 (request->type == NBD_CMD_WRITE ||
2123 request->type == NBD_CMD_WRITE_ZEROES ||
2124 request->type == NBD_CMD_TRIM)) {
2125 error_setg(errp, "Export is read-only");
2126 return -EROFS;
2127 }
2128 if (request->from > client->exp->size ||
2129 request->len > client->exp->size - request->from) {
2130 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32
2131 ", Size: %" PRIu64, request->from, request->len,
2132 client->exp->size);
2133 return (request->type == NBD_CMD_WRITE ||
2134 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL;
2135 }
2136 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len,
2137 client->check_align)) {
2138 /*
2139 * The block layer gracefully handles unaligned requests, but
2140 * it's still worth tracing client non-compliance
2141 */
2142 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type),
2143 request->from,
2144 request->len,
2145 client->check_align);
2146 }
2147 valid_flags = NBD_CMD_FLAG_FUA;
2148 if (request->type == NBD_CMD_READ && client->structured_reply) {
2149 valid_flags |= NBD_CMD_FLAG_DF;
2150 } else if (request->type == NBD_CMD_WRITE_ZEROES) {
2151 valid_flags |= NBD_CMD_FLAG_NO_HOLE;
2152 } else if (request->type == NBD_CMD_BLOCK_STATUS) {
2153 valid_flags |= NBD_CMD_FLAG_REQ_ONE;
2154 }
2155 if (request->flags & ~valid_flags) {
2156 error_setg(errp, "unsupported flags for command %s (got 0x%x)",
2157 nbd_cmd_lookup(request->type), request->flags);
2158 return -EINVAL;
2159 }
2160
2161 return 0;
2162 }
2163
2164 /* Send simple reply without a payload, or a structured error
2165 * @error_msg is ignored if @ret >= 0
2166 * Returns 0 if connection is still live, -errno on failure to talk to client
2167 */
2168 static coroutine_fn int nbd_send_generic_reply(NBDClient *client,
2169 uint64_t handle,
2170 int ret,
2171 const char *error_msg,
2172 Error **errp)
2173 {
2174 if (client->structured_reply && ret < 0) {
2175 return nbd_co_send_structured_error(client, handle, -ret, error_msg,
2176 errp);
2177 } else {
2178 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0,
2179 NULL, 0, errp);
2180 }
2181 }
2182
2183 /* Handle NBD_CMD_READ request.
2184 * Return -errno if sending fails. Other errors are reported directly to the
2185 * client as an error reply. */
2186 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request,
2187 uint8_t *data, Error **errp)
2188 {
2189 int ret;
2190 NBDExport *exp = client->exp;
2191
2192 assert(request->type == NBD_CMD_READ || request->type == NBD_CMD_CACHE);
2193
2194 /* XXX: NBD Protocol only documents use of FUA with WRITE */
2195 if (request->flags & NBD_CMD_FLAG_FUA) {
2196 ret = blk_co_flush(exp->blk);
2197 if (ret < 0) {
2198 return nbd_send_generic_reply(client, request->handle, ret,
2199 "flush failed", errp);
2200 }
2201 }
2202
2203 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) &&
2204 request->len && request->type != NBD_CMD_CACHE)
2205 {
2206 return nbd_co_send_sparse_read(client, request->handle, request->from,
2207 data, request->len, errp);
2208 }
2209
2210 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data,
2211 request->len);
2212 if (ret < 0 || request->type == NBD_CMD_CACHE) {
2213 return nbd_send_generic_reply(client, request->handle, ret,
2214 "reading from file failed", errp);
2215 }
2216
2217 if (client->structured_reply) {
2218 if (request->len) {
2219 return nbd_co_send_structured_read(client, request->handle,
2220 request->from, data,
2221 request->len, true, errp);
2222 } else {
2223 return nbd_co_send_structured_done(client, request->handle, errp);
2224 }
2225 } else {
2226 return nbd_co_send_simple_reply(client, request->handle, 0,
2227 data, request->len, errp);
2228 }
2229 }
2230
2231 /* Handle NBD request.
2232 * Return -errno if sending fails. Other errors are reported directly to the
2233 * client as an error reply. */
2234 static coroutine_fn int nbd_handle_request(NBDClient *client,
2235 NBDRequest *request,
2236 uint8_t *data, Error **errp)
2237 {
2238 int ret;
2239 int flags;
2240 NBDExport *exp = client->exp;
2241 char *msg;
2242
2243 switch (request->type) {
2244 case NBD_CMD_READ:
2245 case NBD_CMD_CACHE:
2246 return nbd_do_cmd_read(client, request, data, errp);
2247
2248 case NBD_CMD_WRITE:
2249 flags = 0;
2250 if (request->flags & NBD_CMD_FLAG_FUA) {
2251 flags |= BDRV_REQ_FUA;
2252 }
2253 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset,
2254 data, request->len, flags);
2255 return nbd_send_generic_reply(client, request->handle, ret,
2256 "writing to file failed", errp);
2257
2258 case NBD_CMD_WRITE_ZEROES:
2259 flags = 0;
2260 if (request->flags & NBD_CMD_FLAG_FUA) {
2261 flags |= BDRV_REQ_FUA;
2262 }
2263 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) {
2264 flags |= BDRV_REQ_MAY_UNMAP;
2265 }
2266 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset,
2267 request->len, flags);
2268 return nbd_send_generic_reply(client, request->handle, ret,
2269 "writing to file failed", errp);
2270
2271 case NBD_CMD_DISC:
2272 /* unreachable, thanks to special case in nbd_co_receive_request() */
2273 abort();
2274
2275 case NBD_CMD_FLUSH:
2276 ret = blk_co_flush(exp->blk);
2277 return nbd_send_generic_reply(client, request->handle, ret,
2278 "flush failed", errp);
2279
2280 case NBD_CMD_TRIM:
2281 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset,
2282 request->len);
2283 if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) {
2284 ret = blk_co_flush(exp->blk);
2285 }
2286 return nbd_send_generic_reply(client, request->handle, ret,
2287 "discard failed", errp);
2288
2289 case NBD_CMD_BLOCK_STATUS:
2290 if (!request->len) {
2291 return nbd_send_generic_reply(client, request->handle, -EINVAL,
2292 "need non-zero length", errp);
2293 }
2294 if (client->export_meta.valid &&
2295 (client->export_meta.base_allocation ||
2296 client->export_meta.bitmap))
2297 {
2298 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE;
2299
2300 if (client->export_meta.base_allocation) {
2301 ret = nbd_co_send_block_status(client, request->handle,
2302 blk_bs(exp->blk), request->from,
2303 request->len, dont_fragment,
2304 !client->export_meta.bitmap,
2305 NBD_META_ID_BASE_ALLOCATION,
2306 errp);
2307 if (ret < 0) {
2308 return ret;
2309 }
2310 }
2311
2312 if (client->export_meta.bitmap) {
2313 ret = nbd_co_send_bitmap(client, request->handle,
2314 client->exp->export_bitmap,
2315 request->from, request->len,
2316 dont_fragment,
2317 true, NBD_META_ID_DIRTY_BITMAP, errp);
2318 if (ret < 0) {
2319 return ret;
2320 }
2321 }
2322
2323 return ret;
2324 } else {
2325 return nbd_send_generic_reply(client, request->handle, -EINVAL,
2326 "CMD_BLOCK_STATUS not negotiated",
2327 errp);
2328 }
2329
2330 default:
2331 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received",
2332 request->type);
2333 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg,
2334 errp);
2335 g_free(msg);
2336 return ret;
2337 }
2338 }
2339
2340 /* Owns a reference to the NBDClient passed as opaque. */
2341 static coroutine_fn void nbd_trip(void *opaque)
2342 {
2343 NBDClient *client = opaque;
2344 NBDRequestData *req;
2345 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */
2346 int ret;
2347 Error *local_err = NULL;
2348
2349 trace_nbd_trip();
2350 if (client->closing) {
2351 nbd_client_put(client);
2352 return;
2353 }
2354
2355 req = nbd_request_get(client);
2356 ret = nbd_co_receive_request(req, &request, &local_err);
2357 client->recv_coroutine = NULL;
2358
2359 if (client->closing) {
2360 /*
2361 * The client may be closed when we are blocked in
2362 * nbd_co_receive_request()
2363 */
2364 goto done;
2365 }
2366
2367 nbd_client_receive_next_request(client);
2368 if (ret == -EIO) {
2369 goto disconnect;
2370 }
2371
2372 if (ret < 0) {
2373 /* It wans't -EIO, so, according to nbd_co_receive_request()
2374 * semantics, we should return the error to the client. */
2375 Error *export_err = local_err;
2376
2377 local_err = NULL;
2378 ret = nbd_send_generic_reply(client, request.handle, -EINVAL,
2379 error_get_pretty(export_err), &local_err);
2380 error_free(export_err);
2381 } else {
2382 ret = nbd_handle_request(client, &request, req->data, &local_err);
2383 }
2384 if (ret < 0) {
2385 error_prepend(&local_err, "Failed to send reply: ");
2386 goto disconnect;
2387 }
2388
2389 /* We must disconnect after NBD_CMD_WRITE if we did not
2390 * read the payload.
2391 */
2392 if (!req->complete) {
2393 error_setg(&local_err, "Request handling failed in intermediate state");
2394 goto disconnect;
2395 }
2396
2397 done:
2398 nbd_request_put(req);
2399 nbd_client_put(client);
2400 return;
2401
2402 disconnect:
2403 if (local_err) {
2404 error_reportf_err(local_err, "Disconnect client, due to: ");
2405 }
2406 nbd_request_put(req);
2407 client_close(client, true);
2408 nbd_client_put(client);
2409 }
2410
2411 static void nbd_client_receive_next_request(NBDClient *client)
2412 {
2413 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) {
2414 nbd_client_get(client);
2415 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
2416 aio_co_schedule(client->exp->ctx, client->recv_coroutine);
2417 }
2418 }
2419
2420 static coroutine_fn void nbd_co_client_start(void *opaque)
2421 {
2422 NBDClient *client = opaque;
2423 Error *local_err = NULL;
2424
2425 qemu_co_mutex_init(&client->send_lock);
2426
2427 if (nbd_negotiate(client, &local_err)) {
2428 if (local_err) {
2429 error_report_err(local_err);
2430 }
2431 client_close(client, false);
2432 return;
2433 }
2434
2435 nbd_client_receive_next_request(client);
2436 }
2437
2438 /*
2439 * Create a new client listener using the given channel @sioc.
2440 * Begin servicing it in a coroutine. When the connection closes, call
2441 * @close_fn with an indication of whether the client completed negotiation.
2442 */
2443 void nbd_client_new(QIOChannelSocket *sioc,
2444 QCryptoTLSCreds *tlscreds,
2445 const char *tlsauthz,
2446 void (*close_fn)(NBDClient *, bool))
2447 {
2448 NBDClient *client;
2449 Coroutine *co;
2450
2451 client = g_new0(NBDClient, 1);
2452 client->refcount = 1;
2453 client->tlscreds = tlscreds;
2454 if (tlscreds) {
2455 object_ref(OBJECT(client->tlscreds));
2456 }
2457 client->tlsauthz = g_strdup(tlsauthz);
2458 client->sioc = sioc;
2459 object_ref(OBJECT(client->sioc));
2460 client->ioc = QIO_CHANNEL(sioc);
2461 object_ref(OBJECT(client->ioc));
2462 client->close_fn = close_fn;
2463
2464 co = qemu_coroutine_create(nbd_co_client_start, client);
2465 qemu_coroutine_enter(co);
2466 }
AR7 emulation for QEMU