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test-filter-mirror: pass UNIX domain socket through fd
[qemu/kevin.git] / nbd / server.c
blobcb0d5634fa1d747360d7d2e3bbb760d719cd6865
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 *tlsaclname;
115 QIOChannelSocket *sioc; /* The underlying data channel */
116 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
117
118 Coroutine *recv_coroutine;
119
120 CoMutex send_lock;
121 Coroutine *send_coroutine;
122
123 QTAILQ_ENTRY(NBDClient) next;
124 int nb_requests;
125 bool closing;
126
127 bool structured_reply;
128 NBDExportMetaContexts export_meta;
129
130 uint32_t opt; /* Current option being negotiated */
131 uint32_t optlen; /* remaining length of data in ioc for the option being
132 negotiated now */
133 };
134
135 static void nbd_client_receive_next_request(NBDClient *client);
136
137 /* Basic flow for negotiation
138
139 Server Client
140 Negotiate
141
142 or
143
144 Server Client
145 Negotiate #1
146 Option
147 Negotiate #2
148
149 ----
150
151 followed by
152
153 Server Client
154 Request
155 Response
156 Request
157 Response
158 ...
159 ...
160 Request (type == 2)
161
162 */
163
164 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option,
165 uint32_t type, uint32_t length)
166 {
167 stq_be_p(&rep->magic, NBD_REP_MAGIC);
168 stl_be_p(&rep->option, option);
169 stl_be_p(&rep->type, type);
170 stl_be_p(&rep->length, length);
171 }
172
173 /* Send a reply header, including length, but no payload.
174 * Return -errno on error, 0 on success. */
175 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type,
176 uint32_t len, Error **errp)
177 {
178 NBDOptionReply rep;
179
180 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt),
181 type, nbd_rep_lookup(type), len);
182
183 assert(len < NBD_MAX_BUFFER_SIZE);
184
185 set_be_option_rep(&rep, client->opt, type, len);
186 return nbd_write(client->ioc, &rep, sizeof(rep), errp);
187 }
188
189 /* Send a reply header with default 0 length.
190 * Return -errno on error, 0 on success. */
191 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type,
192 Error **errp)
193 {
194 return nbd_negotiate_send_rep_len(client, type, 0, errp);
195 }
196
197 /* Send an error reply.
198 * Return -errno on error, 0 on success. */
199 static int GCC_FMT_ATTR(4, 0)
200 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,
201 Error **errp, const char *fmt, va_list va)
202 {
203 char *msg;
204 int ret;
205 size_t len;
206
207 msg = g_strdup_vprintf(fmt, va);
208 len = strlen(msg);
209 assert(len < 4096);
210 trace_nbd_negotiate_send_rep_err(msg);
211 ret = nbd_negotiate_send_rep_len(client, type, len, errp);
212 if (ret < 0) {
213 goto out;
214 }
215 if (nbd_write(client->ioc, msg, len, errp) < 0) {
216 error_prepend(errp, "write failed (error message): ");
217 ret = -EIO;
218 } else {
219 ret = 0;
220 }
221
222 out:
223 g_free(msg);
224 return ret;
225 }
226
227 /* Send an error reply.
228 * Return -errno on error, 0 on success. */
229 static int GCC_FMT_ATTR(4, 5)
230 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type,
231 Error **errp, const char *fmt, ...)
232 {
233 va_list va;
234 int ret;
235
236 va_start(va, fmt);
237 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
238 va_end(va);
239 return ret;
240 }
241
242 /* Drop remainder of the current option, and send a reply with the
243 * given error type and message. Return -errno on read or write
244 * failure; or 0 if connection is still live. */
245 static int GCC_FMT_ATTR(4, 0)
246 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp,
247 const char *fmt, va_list va)
248 {
249 int ret = nbd_drop(client->ioc, client->optlen, errp);
250
251 client->optlen = 0;
252 if (!ret) {
253 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
254 }
255 return ret;
256 }
257
258 static int GCC_FMT_ATTR(4, 5)
259 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp,
260 const char *fmt, ...)
261 {
262 int ret;
263 va_list va;
264
265 va_start(va, fmt);
266 ret = nbd_opt_vdrop(client, type, errp, fmt, va);
267 va_end(va);
268
269 return ret;
270 }
271
272 static int GCC_FMT_ATTR(3, 4)
273 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...)
274 {
275 int ret;
276 va_list va;
277
278 va_start(va, fmt);
279 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va);
280 va_end(va);
281
282 return ret;
283 }
284
285 /* Read size bytes from the unparsed payload of the current option.
286 * Return -errno on I/O error, 0 if option was completely handled by
287 * sending a reply about inconsistent lengths, or 1 on success. */
288 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size,
289 Error **errp)
290 {
291 if (size > client->optlen) {
292 return nbd_opt_invalid(client, errp,
293 "Inconsistent lengths in option %s",
294 nbd_opt_lookup(client->opt));
295 }
296 client->optlen -= size;
297 return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1;
298 }
299
300 /* Drop size bytes from the unparsed payload of the current option.
301 * Return -errno on I/O error, 0 if option was completely handled by
302 * sending a reply about inconsistent lengths, or 1 on success. */
303 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp)
304 {
305 if (size > client->optlen) {
306 return nbd_opt_invalid(client, errp,
307 "Inconsistent lengths in option %s",
308 nbd_opt_lookup(client->opt));
309 }
310 client->optlen -= size;
311 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1;
312 }
313
314 /* nbd_opt_read_name
315 *
316 * Read a string with the format:
317 * uint32_t len (<= NBD_MAX_NAME_SIZE)
318 * len bytes string (not 0-terminated)
319 *
320 * @name should be enough to store NBD_MAX_NAME_SIZE+1.
321 * If @length is non-null, it will be set to the actual string length.
322 *
323 * Return -errno on I/O error, 0 if option was completely handled by
324 * sending a reply about inconsistent lengths, or 1 on success.
325 */
326 static int nbd_opt_read_name(NBDClient *client, char *name, uint32_t *length,
327 Error **errp)
328 {
329 int ret;
330 uint32_t len;
331
332 ret = nbd_opt_read(client, &len, sizeof(len), errp);
333 if (ret <= 0) {
334 return ret;
335 }
336 len = cpu_to_be32(len);
337
338 if (len > NBD_MAX_NAME_SIZE) {
339 return nbd_opt_invalid(client, errp,
340 "Invalid name length: %" PRIu32, len);
341 }
342
343 ret = nbd_opt_read(client, name, len, errp);
344 if (ret <= 0) {
345 return ret;
346 }
347 name[len] = '\0';
348
349 if (length) {
350 *length = len;
351 }
352
353 return 1;
354 }
355
356 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
357 * Return -errno on error, 0 on success. */
358 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp,
359 Error **errp)
360 {
361 size_t name_len, desc_len;
362 uint32_t len;
363 const char *name = exp->name ? exp->name : "";
364 const char *desc = exp->description ? exp->description : "";
365 QIOChannel *ioc = client->ioc;
366 int ret;
367
368 trace_nbd_negotiate_send_rep_list(name, desc);
369 name_len = strlen(name);
370 desc_len = strlen(desc);
371 len = name_len + desc_len + sizeof(len);
372 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp);
373 if (ret < 0) {
374 return ret;
375 }
376
377 len = cpu_to_be32(name_len);
378 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
379 error_prepend(errp, "write failed (name length): ");
380 return -EINVAL;
381 }
382
383 if (nbd_write(ioc, name, name_len, errp) < 0) {
384 error_prepend(errp, "write failed (name buffer): ");
385 return -EINVAL;
386 }
387
388 if (nbd_write(ioc, desc, desc_len, errp) < 0) {
389 error_prepend(errp, "write failed (description buffer): ");
390 return -EINVAL;
391 }
392
393 return 0;
394 }
395
396 /* Process the NBD_OPT_LIST command, with a potential series of replies.
397 * Return -errno on error, 0 on success. */
398 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)
399 {
400 NBDExport *exp;
401 assert(client->opt == NBD_OPT_LIST);
402
403 /* For each export, send a NBD_REP_SERVER reply. */
404 QTAILQ_FOREACH(exp, &exports, next) {
405 if (nbd_negotiate_send_rep_list(client, exp, errp)) {
406 return -EINVAL;
407 }
408 }
409 /* Finish with a NBD_REP_ACK. */
410 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
411 }
412
413 static void nbd_check_meta_export(NBDClient *client)
414 {
415 client->export_meta.valid &= client->exp == client->export_meta.exp;
416 }
417
418 /* Send a reply to NBD_OPT_EXPORT_NAME.
419 * Return -errno on error, 0 on success. */
420 static int nbd_negotiate_handle_export_name(NBDClient *client,
421 uint16_t myflags, bool no_zeroes,
422 Error **errp)
423 {
424 char name[NBD_MAX_NAME_SIZE + 1];
425 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
426 size_t len;
427 int ret;
428
429 /* Client sends:
430 [20 .. xx] export name (length bytes)
431 Server replies:
432 [ 0 .. 7] size
433 [ 8 .. 9] export flags
434 [10 .. 133] reserved (0) [unless no_zeroes]
435 */
436 trace_nbd_negotiate_handle_export_name();
437 if (client->optlen >= sizeof(name)) {
438 error_setg(errp, "Bad length received");
439 return -EINVAL;
440 }
441 if (nbd_read(client->ioc, name, client->optlen, errp) < 0) {
442 error_prepend(errp, "read failed: ");
443 return -EIO;
444 }
445 name[client->optlen] = '\0';
446 client->optlen = 0;
447
448 trace_nbd_negotiate_handle_export_name_request(name);
449
450 client->exp = nbd_export_find(name);
451 if (!client->exp) {
452 error_setg(errp, "export not found");
453 return -EINVAL;
454 }
455
456 trace_nbd_negotiate_new_style_size_flags(client->exp->size,
457 client->exp->nbdflags | myflags);
458 stq_be_p(buf, client->exp->size);
459 stw_be_p(buf + 8, client->exp->nbdflags | myflags);
460 len = no_zeroes ? 10 : sizeof(buf);
461 ret = nbd_write(client->ioc, buf, len, errp);
462 if (ret < 0) {
463 error_prepend(errp, "write failed: ");
464 return ret;
465 }
466
467 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
468 nbd_export_get(client->exp);
469 nbd_check_meta_export(client);
470
471 return 0;
472 }
473
474 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
475 * The buffer does NOT include the info type prefix.
476 * Return -errno on error, 0 if ready to send more. */
477 static int nbd_negotiate_send_info(NBDClient *client,
478 uint16_t info, uint32_t length, void *buf,
479 Error **errp)
480 {
481 int rc;
482
483 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);
484 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO,
485 sizeof(info) + length, errp);
486 if (rc < 0) {
487 return rc;
488 }
489 info = cpu_to_be16(info);
490 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) {
491 return -EIO;
492 }
493 if (nbd_write(client->ioc, buf, length, errp) < 0) {
494 return -EIO;
495 }
496 return 0;
497 }
498
499 /* nbd_reject_length: Handle any unexpected payload.
500 * @fatal requests that we quit talking to the client, even if we are able
501 * to successfully send an error reply.
502 * Return:
503 * -errno transmission error occurred or @fatal was requested, errp is set
504 * 0 error message successfully sent to client, errp is not set
505 */
506 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp)
507 {
508 int ret;
509
510 assert(client->optlen);
511 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length",
512 nbd_opt_lookup(client->opt));
513 if (fatal && !ret) {
514 error_setg(errp, "option '%s' has unexpected length",
515 nbd_opt_lookup(client->opt));
516 return -EINVAL;
517 }
518 return ret;
519 }
520
521 /* Handle NBD_OPT_INFO and NBD_OPT_GO.
522 * Return -errno on error, 0 if ready for next option, and 1 to move
523 * into transmission phase. */
524 static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,
525 Error **errp)
526 {
527 int rc;
528 char name[NBD_MAX_NAME_SIZE + 1];
529 NBDExport *exp;
530 uint16_t requests;
531 uint16_t request;
532 uint32_t namelen;
533 bool sendname = false;
534 bool blocksize = false;
535 uint32_t sizes[3];
536 char buf[sizeof(uint64_t) + sizeof(uint16_t)];
537
538 /* Client sends:
539 4 bytes: L, name length (can be 0)
540 L bytes: export name
541 2 bytes: N, number of requests (can be 0)
542 N * 2 bytes: N requests
543 */
544 rc = nbd_opt_read_name(client, name, &namelen, errp);
545 if (rc <= 0) {
546 return rc;
547 }
548 trace_nbd_negotiate_handle_export_name_request(name);
549
550 rc = nbd_opt_read(client, &requests, sizeof(requests), errp);
551 if (rc <= 0) {
552 return rc;
553 }
554 requests = be16_to_cpu(requests);
555 trace_nbd_negotiate_handle_info_requests(requests);
556 while (requests--) {
557 rc = nbd_opt_read(client, &request, sizeof(request), errp);
558 if (rc <= 0) {
559 return rc;
560 }
561 request = be16_to_cpu(request);
562 trace_nbd_negotiate_handle_info_request(request,
563 nbd_info_lookup(request));
564 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;
565 * everything else is either a request we don't know or
566 * something we send regardless of request */
567 switch (request) {
568 case NBD_INFO_NAME:
569 sendname = true;
570 break;
571 case NBD_INFO_BLOCK_SIZE:
572 blocksize = true;
573 break;
574 }
575 }
576 if (client->optlen) {
577 return nbd_reject_length(client, false, errp);
578 }
579
580 exp = nbd_export_find(name);
581 if (!exp) {
582 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN,
583 errp, "export '%s' not present",
584 name);
585 }
586
587 /* Don't bother sending NBD_INFO_NAME unless client requested it */
588 if (sendname) {
589 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name,
590 errp);
591 if (rc < 0) {
592 return rc;
593 }
594 }
595
596 /* Send NBD_INFO_DESCRIPTION only if available, regardless of
597 * client request */
598 if (exp->description) {
599 size_t len = strlen(exp->description);
600
601 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION,
602 len, exp->description, errp);
603 if (rc < 0) {
604 return rc;
605 }
606 }
607
608 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size
609 * according to whether the client requested it, and according to
610 * whether this is OPT_INFO or OPT_GO. */
611 /* minimum - 1 for back-compat, or 512 if client is new enough.
612 * TODO: consult blk_bs(blk)->bl.request_alignment? */
613 sizes[0] =
614 (client->opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1;
615 /* preferred - Hard-code to 4096 for now.
616 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */
617 sizes[1] = 4096;
618 /* maximum - At most 32M, but smaller as appropriate. */
619 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE);
620 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]);
621 sizes[0] = cpu_to_be32(sizes[0]);
622 sizes[1] = cpu_to_be32(sizes[1]);
623 sizes[2] = cpu_to_be32(sizes[2]);
624 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE,
625 sizeof(sizes), sizes, errp);
626 if (rc < 0) {
627 return rc;
628 }
629
630 /* Send NBD_INFO_EXPORT always */
631 trace_nbd_negotiate_new_style_size_flags(exp->size,
632 exp->nbdflags | myflags);
633 stq_be_p(buf, exp->size);
634 stw_be_p(buf + 8, exp->nbdflags | myflags);
635 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT,
636 sizeof(buf), buf, errp);
637 if (rc < 0) {
638 return rc;
639 }
640
641 /* If the client is just asking for NBD_OPT_INFO, but forgot to
642 * request block sizes, return an error.
643 * TODO: consult blk_bs(blk)->request_align, and only error if it
644 * is not 1? */
645 if (client->opt == NBD_OPT_INFO && !blocksize) {
646 return nbd_negotiate_send_rep_err(client,
647 NBD_REP_ERR_BLOCK_SIZE_REQD,
648 errp,
649 "request NBD_INFO_BLOCK_SIZE to "
650 "use this export");
651 }
652
653 /* Final reply */
654 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
655 if (rc < 0) {
656 return rc;
657 }
658
659 if (client->opt == NBD_OPT_GO) {
660 client->exp = exp;
661 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
662 nbd_export_get(client->exp);
663 nbd_check_meta_export(client);
664 rc = 1;
665 }
666 return rc;
667 }
668
669
670 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
671 * new channel for all further (now-encrypted) communication. */
672 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
673 Error **errp)
674 {
675 QIOChannel *ioc;
676 QIOChannelTLS *tioc;
677 struct NBDTLSHandshakeData data = { 0 };
678
679 assert(client->opt == NBD_OPT_STARTTLS);
680
681 trace_nbd_negotiate_handle_starttls();
682 ioc = client->ioc;
683
684 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) {
685 return NULL;
686 }
687
688 tioc = qio_channel_tls_new_server(ioc,
689 client->tlscreds,
690 client->tlsaclname,
691 errp);
692 if (!tioc) {
693 return NULL;
694 }
695
696 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
697 trace_nbd_negotiate_handle_starttls_handshake();
698 data.loop = g_main_loop_new(g_main_context_default(), FALSE);
699 qio_channel_tls_handshake(tioc,
700 nbd_tls_handshake,
701 &data,
702 NULL,
703 NULL);
704
705 if (!data.complete) {
706 g_main_loop_run(data.loop);
707 }
708 g_main_loop_unref(data.loop);
709 if (data.error) {
710 object_unref(OBJECT(tioc));
711 error_propagate(errp, data.error);
712 return NULL;
713 }
714
715 return QIO_CHANNEL(tioc);
716 }
717
718 /* nbd_negotiate_send_meta_context
719 *
720 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT
721 *
722 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead.
723 */
724 static int nbd_negotiate_send_meta_context(NBDClient *client,
725 const char *context,
726 uint32_t context_id,
727 Error **errp)
728 {
729 NBDOptionReplyMetaContext opt;
730 struct iovec iov[] = {
731 {.iov_base = &opt, .iov_len = sizeof(opt)},
732 {.iov_base = (void *)context, .iov_len = strlen(context)}
733 };
734
735 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
736 context_id = 0;
737 }
738
739 trace_nbd_negotiate_meta_query_reply(context, context_id);
740 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT,
741 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len);
742 stl_be_p(&opt.context_id, context_id);
743
744 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0;
745 }
746
747 /* Read strlen(@pattern) bytes, and set @match to true if they match @pattern.
748 * @match is never set to false.
749 *
750 * Return -errno on I/O error, 0 if option was completely handled by
751 * sending a reply about inconsistent lengths, or 1 on success.
752 *
753 * Note: return code = 1 doesn't mean that we've read exactly @pattern.
754 * It only means that there are no errors.
755 */
756 static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match,
757 Error **errp)
758 {
759 int ret;
760 char *query;
761 size_t len = strlen(pattern);
762
763 assert(len);
764
765 query = g_malloc(len);
766 ret = nbd_opt_read(client, query, len, errp);
767 if (ret <= 0) {
768 g_free(query);
769 return ret;
770 }
771
772 if (strncmp(query, pattern, len) == 0) {
773 trace_nbd_negotiate_meta_query_parse(pattern);
774 *match = true;
775 } else {
776 trace_nbd_negotiate_meta_query_skip("pattern not matched");
777 }
778 g_free(query);
779
780 return 1;
781 }
782
783 /*
784 * Read @len bytes, and set @match to true if they match @pattern, or if @len
785 * is 0 and the client is performing _LIST_. @match is never set to false.
786 *
787 * Return -errno on I/O error, 0 if option was completely handled by
788 * sending a reply about inconsistent lengths, or 1 on success.
789 *
790 * Note: return code = 1 doesn't mean that we've read exactly @pattern.
791 * It only means that there are no errors.
792 */
793 static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
794 uint32_t len, bool *match, Error **errp)
795 {
796 if (len == 0) {
797 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
798 *match = true;
799 }
800 trace_nbd_negotiate_meta_query_parse("empty");
801 return 1;
802 }
803
804 if (len != strlen(pattern)) {
805 trace_nbd_negotiate_meta_query_skip("different lengths");
806 return nbd_opt_skip(client, len, errp);
807 }
808
809 return nbd_meta_pattern(client, pattern, match, errp);
810 }
811
812 /* nbd_meta_base_query
813 *
814 * Handle queries to 'base' namespace. For now, only the base:allocation
815 * context is available. 'len' is the amount of text remaining to be read from
816 * the current name, after the 'base:' portion has been stripped.
817 *
818 * Return -errno on I/O error, 0 if option was completely handled by
819 * sending a reply about inconsistent lengths, or 1 on success.
820 */
821 static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
822 uint32_t len, Error **errp)
823 {
824 return nbd_meta_empty_or_pattern(client, "allocation", len,
825 &meta->base_allocation, errp);
826 }
827
828 /* nbd_meta_bitmap_query
829 *
830 * Handle query to 'qemu:' namespace.
831 * @len is the amount of text remaining to be read from the current name, after
832 * the 'qemu:' portion has been stripped.
833 *
834 * Return -errno on I/O error, 0 if option was completely handled by
835 * sending a reply about inconsistent lengths, or 1 on success. */
836 static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta,
837 uint32_t len, Error **errp)
838 {
839 bool dirty_bitmap = false;
840 size_t dirty_bitmap_len = strlen("dirty-bitmap:");
841 int ret;
842
843 if (!meta->exp->export_bitmap) {
844 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported");
845 return nbd_opt_skip(client, len, errp);
846 }
847
848 if (len == 0) {
849 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
850 meta->bitmap = true;
851 }
852 trace_nbd_negotiate_meta_query_parse("empty");
853 return 1;
854 }
855
856 if (len < dirty_bitmap_len) {
857 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");
858 return nbd_opt_skip(client, len, errp);
859 }
860
861 len -= dirty_bitmap_len;
862 ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp);
863 if (ret <= 0) {
864 return ret;
865 }
866 if (!dirty_bitmap) {
867 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");
868 return nbd_opt_skip(client, len, errp);
869 }
870
871 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:");
872
873 return nbd_meta_empty_or_pattern(
874 client, meta->exp->export_bitmap_context +
875 strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp);
876 }
877
878 /* nbd_negotiate_meta_query
879 *
880 * Parse namespace name and call corresponding function to parse body of the
881 * query.
882 *
883 * The only supported namespace now is 'base'.
884 *
885 * The function aims not wasting time and memory to read long unknown namespace
886 * names.
887 *
888 * Return -errno on I/O error, 0 if option was completely handled by
889 * sending a reply about inconsistent lengths, or 1 on success. */
890 static int nbd_negotiate_meta_query(NBDClient *client,
891 NBDExportMetaContexts *meta, Error **errp)
892 {
893 /*
894 * Both 'qemu' and 'base' namespaces have length = 5 including a
895 * colon. If another length namespace is later introduced, this
896 * should certainly be refactored.
897 */
898 int ret;
899 size_t ns_len = 5;
900 char ns[5];
901 uint32_t len;
902
903 ret = nbd_opt_read(client, &len, sizeof(len), errp);
904 if (ret <= 0) {
905 return ret;
906 }
907 len = cpu_to_be32(len);
908
909 if (len < ns_len) {
910 trace_nbd_negotiate_meta_query_skip("length too short");
911 return nbd_opt_skip(client, len, errp);
912 }
913
914 len -= ns_len;
915 ret = nbd_opt_read(client, ns, ns_len, errp);
916 if (ret <= 0) {
917 return ret;
918 }
919
920 if (!strncmp(ns, "base:", ns_len)) {
921 trace_nbd_negotiate_meta_query_parse("base:");
922 return nbd_meta_base_query(client, meta, len, errp);
923 } else if (!strncmp(ns, "qemu:", ns_len)) {
924 trace_nbd_negotiate_meta_query_parse("qemu:");
925 return nbd_meta_qemu_query(client, meta, len, errp);
926 }
927
928 trace_nbd_negotiate_meta_query_skip("unknown namespace");
929 return nbd_opt_skip(client, len, errp);
930 }
931
932 /* nbd_negotiate_meta_queries
933 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT
934 *
935 * Return -errno on I/O error, or 0 if option was completely handled. */
936 static int nbd_negotiate_meta_queries(NBDClient *client,
937 NBDExportMetaContexts *meta, Error **errp)
938 {
939 int ret;
940 char export_name[NBD_MAX_NAME_SIZE + 1];
941 NBDExportMetaContexts local_meta;
942 uint32_t nb_queries;
943 int i;
944
945 if (!client->structured_reply) {
946 return nbd_opt_invalid(client, errp,
947 "request option '%s' when structured reply "
948 "is not negotiated",
949 nbd_opt_lookup(client->opt));
950 }
951
952 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
953 /* Only change the caller's meta on SET. */
954 meta = &local_meta;
955 }
956
957 memset(meta, 0, sizeof(*meta));
958
959 ret = nbd_opt_read_name(client, export_name, NULL, errp);
960 if (ret <= 0) {
961 return ret;
962 }
963
964 meta->exp = nbd_export_find(export_name);
965 if (meta->exp == NULL) {
966 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp,
967 "export '%s' not present", export_name);
968 }
969
970 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp);
971 if (ret <= 0) {
972 return ret;
973 }
974 nb_queries = cpu_to_be32(nb_queries);
975 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt),
976 export_name, nb_queries);
977
978 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) {
979 /* enable all known contexts */
980 meta->base_allocation = true;
981 meta->bitmap = !!meta->exp->export_bitmap;
982 } else {
983 for (i = 0; i < nb_queries; ++i) {
984 ret = nbd_negotiate_meta_query(client, meta, errp);
985 if (ret <= 0) {
986 return ret;
987 }
988 }
989 }
990
991 if (meta->base_allocation) {
992 ret = nbd_negotiate_send_meta_context(client, "base:allocation",
993 NBD_META_ID_BASE_ALLOCATION,
994 errp);
995 if (ret < 0) {
996 return ret;
997 }
998 }
999
1000 if (meta->bitmap) {
1001 ret = nbd_negotiate_send_meta_context(client,
1002 meta->exp->export_bitmap_context,
1003 NBD_META_ID_DIRTY_BITMAP,
1004 errp);
1005 if (ret < 0) {
1006 return ret;
1007 }
1008 }
1009
1010 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1011 if (ret == 0) {
1012 meta->valid = true;
1013 }
1014
1015 return ret;
1016 }
1017
1018 /* nbd_negotiate_options
1019 * Process all NBD_OPT_* client option commands, during fixed newstyle
1020 * negotiation.
1021 * Return:
1022 * -errno on error, errp is set
1023 * 0 on successful negotiation, errp is not set
1024 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
1025 * errp is not set
1026 */
1027 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
1028 Error **errp)
1029 {
1030 uint32_t flags;
1031 bool fixedNewstyle = false;
1032 bool no_zeroes = false;
1033
1034 /* Client sends:
1035 [ 0 .. 3] client flags
1036
1037 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO:
1038 [ 0 .. 7] NBD_OPTS_MAGIC
1039 [ 8 .. 11] NBD option
1040 [12 .. 15] Data length
1041 ... Rest of request
1042
1043 [ 0 .. 7] NBD_OPTS_MAGIC
1044 [ 8 .. 11] Second NBD option
1045 [12 .. 15] Data length
1046 ... Rest of request
1047 */
1048
1049 if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) {
1050 error_prepend(errp, "read failed: ");
1051 return -EIO;
1052 }
1053 flags = be32_to_cpu(flags);
1054 trace_nbd_negotiate_options_flags(flags);
1055 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
1056 fixedNewstyle = true;
1057 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
1058 }
1059 if (flags & NBD_FLAG_C_NO_ZEROES) {
1060 no_zeroes = true;
1061 flags &= ~NBD_FLAG_C_NO_ZEROES;
1062 }
1063 if (flags != 0) {
1064 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);
1065 return -EINVAL;
1066 }
1067
1068 while (1) {
1069 int ret;
1070 uint32_t option, length;
1071 uint64_t magic;
1072
1073 if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) {
1074 error_prepend(errp, "read failed: ");
1075 return -EINVAL;
1076 }
1077 magic = be64_to_cpu(magic);
1078 trace_nbd_negotiate_options_check_magic(magic);
1079 if (magic != NBD_OPTS_MAGIC) {
1080 error_setg(errp, "Bad magic received");
1081 return -EINVAL;
1082 }
1083
1084 if (nbd_read(client->ioc, &option,
1085 sizeof(option), errp) < 0) {
1086 error_prepend(errp, "read failed: ");
1087 return -EINVAL;
1088 }
1089 option = be32_to_cpu(option);
1090 client->opt = option;
1091
1092 if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) {
1093 error_prepend(errp, "read failed: ");
1094 return -EINVAL;
1095 }
1096 length = be32_to_cpu(length);
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), 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->tlsaclname);
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 BlockDriverState *bs = blk_bs(blk);
1509
1510 while (true) {
1511 bm = bdrv_find_dirty_bitmap(bs, bitmap);
1512 if (bm != NULL || bs->backing == NULL) {
1513 break;
1514 }
1515
1516 bs = bs->backing->bs;
1517 }
1518
1519 if (bm == NULL) {
1520 error_setg(errp, "Bitmap '%s' is not found", bitmap);
1521 goto fail;
1522 }
1523
1524 if ((nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) &&
1525 bdrv_dirty_bitmap_enabled(bm)) {
1526 error_setg(errp,
1527 "Enabled bitmap '%s' incompatible with readonly export",
1528 bitmap);
1529 goto fail;
1530 }
1531
1532 if (bdrv_dirty_bitmap_user_locked(bm)) {
1533 error_setg(errp, "Bitmap '%s' is in use", bitmap);
1534 goto fail;
1535 }
1536
1537 bdrv_dirty_bitmap_set_qmp_locked(bm, true);
1538 exp->export_bitmap = bm;
1539 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s",
1540 bitmap);
1541 }
1542
1543 exp->close = close;
1544 exp->ctx = blk_get_aio_context(blk);
1545 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
1546
1547 if (on_eject_blk) {
1548 blk_ref(on_eject_blk);
1549 exp->eject_notifier_blk = on_eject_blk;
1550 exp->eject_notifier.notify = nbd_eject_notifier;
1551 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
1552 }
1553 QTAILQ_INSERT_TAIL(&exports, exp, next);
1554 nbd_export_get(exp);
1555 return exp;
1556
1557 fail:
1558 blk_unref(blk);
1559 g_free(exp->name);
1560 g_free(exp->description);
1561 g_free(exp);
1562 return NULL;
1563 }
1564
1565 NBDExport *nbd_export_find(const char *name)
1566 {
1567 NBDExport *exp;
1568 QTAILQ_FOREACH(exp, &exports, next) {
1569 if (strcmp(name, exp->name) == 0) {
1570 return exp;
1571 }
1572 }
1573
1574 return NULL;
1575 }
1576
1577 void nbd_export_close(NBDExport *exp)
1578 {
1579 NBDClient *client, *next;
1580
1581 nbd_export_get(exp);
1582 /*
1583 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a
1584 * close mode that stops advertising the export to new clients but
1585 * still permits existing clients to run to completion? Because of
1586 * that possibility, nbd_export_close() can be called more than
1587 * once on an export.
1588 */
1589 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
1590 client_close(client, true);
1591 }
1592 if (exp->name) {
1593 nbd_export_put(exp);
1594 g_free(exp->name);
1595 exp->name = NULL;
1596 QTAILQ_REMOVE(&exports, exp, next);
1597 }
1598 g_free(exp->description);
1599 exp->description = NULL;
1600 nbd_export_put(exp);
1601 }
1602
1603 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp)
1604 {
1605 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) {
1606 nbd_export_close(exp);
1607 return;
1608 }
1609
1610 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE);
1611
1612 error_setg(errp, "export '%s' still in use", exp->name);
1613 error_append_hint(errp, "Use mode='hard' to force client disconnect\n");
1614 }
1615
1616 void nbd_export_get(NBDExport *exp)
1617 {
1618 assert(exp->refcount > 0);
1619 exp->refcount++;
1620 }
1621
1622 void nbd_export_put(NBDExport *exp)
1623 {
1624 assert(exp->refcount > 0);
1625 if (exp->refcount == 1) {
1626 nbd_export_close(exp);
1627 }
1628
1629 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen
1630 * if someone calls nbd_export_put() on named export not through
1631 * nbd_export_set_name() when refcount is 1. So, let's assert that
1632 * it is > 0.
1633 */
1634 assert(exp->refcount > 0);
1635 if (--exp->refcount == 0) {
1636 assert(exp->name == NULL);
1637 assert(exp->description == NULL);
1638
1639 if (exp->close) {
1640 exp->close(exp);
1641 }
1642
1643 if (exp->blk) {
1644 if (exp->eject_notifier_blk) {
1645 notifier_remove(&exp->eject_notifier);
1646 blk_unref(exp->eject_notifier_blk);
1647 }
1648 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
1649 blk_aio_detach, exp);
1650 blk_unref(exp->blk);
1651 exp->blk = NULL;
1652 }
1653
1654 if (exp->export_bitmap) {
1655 bdrv_dirty_bitmap_set_qmp_locked(exp->export_bitmap, false);
1656 g_free(exp->export_bitmap_context);
1657 }
1658
1659 g_free(exp);
1660 }
1661 }
1662
1663 BlockBackend *nbd_export_get_blockdev(NBDExport *exp)
1664 {
1665 return exp->blk;
1666 }
1667
1668 void nbd_export_close_all(void)
1669 {
1670 NBDExport *exp, *next;
1671
1672 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {
1673 nbd_export_close(exp);
1674 }
1675 }
1676
1677 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov,
1678 unsigned niov, Error **errp)
1679 {
1680 int ret;
1681
1682 g_assert(qemu_in_coroutine());
1683 qemu_co_mutex_lock(&client->send_lock);
1684 client->send_coroutine = qemu_coroutine_self();
1685
1686 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0;
1687
1688 client->send_coroutine = NULL;
1689 qemu_co_mutex_unlock(&client->send_lock);
1690
1691 return ret;
1692 }
1693
1694 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,
1695 uint64_t handle)
1696 {
1697 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);
1698 stl_be_p(&reply->error, error);
1699 stq_be_p(&reply->handle, handle);
1700 }
1701
1702 static int nbd_co_send_simple_reply(NBDClient *client,
1703 uint64_t handle,
1704 uint32_t error,
1705 void *data,
1706 size_t len,
1707 Error **errp)
1708 {
1709 NBDSimpleReply reply;
1710 int nbd_err = system_errno_to_nbd_errno(error);
1711 struct iovec iov[] = {
1712 {.iov_base = &reply, .iov_len = sizeof(reply)},
1713 {.iov_base = data, .iov_len = len}
1714 };
1715
1716 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err),
1717 len);
1718 set_be_simple_reply(&reply, nbd_err, handle);
1719
1720 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp);
1721 }
1722
1723 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags,
1724 uint16_t type, uint64_t handle, uint32_t length)
1725 {
1726 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC);
1727 stw_be_p(&chunk->flags, flags);
1728 stw_be_p(&chunk->type, type);
1729 stq_be_p(&chunk->handle, handle);
1730 stl_be_p(&chunk->length, length);
1731 }
1732
1733 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client,
1734 uint64_t handle,
1735 Error **errp)
1736 {
1737 NBDStructuredReplyChunk chunk;
1738 struct iovec iov[] = {
1739 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1740 };
1741
1742 trace_nbd_co_send_structured_done(handle);
1743 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0);
1744
1745 return nbd_co_send_iov(client, iov, 1, errp);
1746 }
1747
1748 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client,
1749 uint64_t handle,
1750 uint64_t offset,
1751 void *data,
1752 size_t size,
1753 bool final,
1754 Error **errp)
1755 {
1756 NBDStructuredReadData chunk;
1757 struct iovec iov[] = {
1758 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1759 {.iov_base = data, .iov_len = size}
1760 };
1761
1762 assert(size);
1763 trace_nbd_co_send_structured_read(handle, offset, data, size);
1764 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
1765 NBD_REPLY_TYPE_OFFSET_DATA, handle,
1766 sizeof(chunk) - sizeof(chunk.h) + size);
1767 stq_be_p(&chunk.offset, offset);
1768
1769 return nbd_co_send_iov(client, iov, 2, errp);
1770 }
1771
1772 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client,
1773 uint64_t handle,
1774 uint32_t error,
1775 const char *msg,
1776 Error **errp)
1777 {
1778 NBDStructuredError chunk;
1779 int nbd_err = system_errno_to_nbd_errno(error);
1780 struct iovec iov[] = {
1781 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1782 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0},
1783 };
1784
1785 assert(nbd_err);
1786 trace_nbd_co_send_structured_error(handle, nbd_err,
1787 nbd_err_lookup(nbd_err), msg ? msg : "");
1788 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle,
1789 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
1790 stl_be_p(&chunk.error, nbd_err);
1791 stw_be_p(&chunk.message_length, iov[1].iov_len);
1792
1793 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp);
1794 }
1795
1796 /* Do a sparse read and send the structured reply to the client.
1797 * Returns -errno if sending fails. bdrv_block_status_above() failure is
1798 * reported to the client, at which point this function succeeds.
1799 */
1800 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
1801 uint64_t handle,
1802 uint64_t offset,
1803 uint8_t *data,
1804 size_t size,
1805 Error **errp)
1806 {
1807 int ret = 0;
1808 NBDExport *exp = client->exp;
1809 size_t progress = 0;
1810
1811 while (progress < size) {
1812 int64_t pnum;
1813 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL,
1814 offset + progress,
1815 size - progress, &pnum, NULL,
1816 NULL);
1817 bool final;
1818
1819 if (status < 0) {
1820 char *msg = g_strdup_printf("unable to check for holes: %s",
1821 strerror(-status));
1822
1823 ret = nbd_co_send_structured_error(client, handle, -status, msg,
1824 errp);
1825 g_free(msg);
1826 return ret;
1827 }
1828 assert(pnum && pnum <= size - progress);
1829 final = progress + pnum == size;
1830 if (status & BDRV_BLOCK_ZERO) {
1831 NBDStructuredReadHole chunk;
1832 struct iovec iov[] = {
1833 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1834 };
1835
1836 trace_nbd_co_send_structured_read_hole(handle, offset + progress,
1837 pnum);
1838 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
1839 NBD_REPLY_TYPE_OFFSET_HOLE,
1840 handle, sizeof(chunk) - sizeof(chunk.h));
1841 stq_be_p(&chunk.offset, offset + progress);
1842 stl_be_p(&chunk.length, pnum);
1843 ret = nbd_co_send_iov(client, iov, 1, errp);
1844 } else {
1845 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset,
1846 data + progress, pnum);
1847 if (ret < 0) {
1848 error_setg_errno(errp, -ret, "reading from file failed");
1849 break;
1850 }
1851 ret = nbd_co_send_structured_read(client, handle, offset + progress,
1852 data + progress, pnum, final,
1853 errp);
1854 }
1855
1856 if (ret < 0) {
1857 break;
1858 }
1859 progress += pnum;
1860 }
1861 return ret;
1862 }
1863
1864 /*
1865 * Populate @extents from block status. Update @bytes to be the actual
1866 * length encoded (which may be smaller than the original), and update
1867 * @nb_extents to the number of extents used.
1868 *
1869 * Returns zero on success and -errno on bdrv_block_status_above failure.
1870 */
1871 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset,
1872 uint64_t *bytes, NBDExtent *extents,
1873 unsigned int *nb_extents)
1874 {
1875 uint64_t remaining_bytes = *bytes;
1876 NBDExtent *extent = extents, *extents_end = extents + *nb_extents;
1877 bool first_extent = true;
1878
1879 assert(*nb_extents);
1880 while (remaining_bytes) {
1881 uint32_t flags;
1882 int64_t num;
1883 int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes,
1884 &num, NULL, NULL);
1885
1886 if (ret < 0) {
1887 return ret;
1888 }
1889
1890 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) |
1891 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0);
1892 offset += num;
1893 remaining_bytes -= num;
1894
1895 if (first_extent) {
1896 extent->flags = flags;
1897 extent->length = num;
1898 first_extent = false;
1899 continue;
1900 }
1901
1902 if (flags == extent->flags) {
1903 /* extend current extent */
1904 extent->length += num;
1905 } else {
1906 if (extent + 1 == extents_end) {
1907 break;
1908 }
1909
1910 /* start new extent */
1911 extent++;
1912 extent->flags = flags;
1913 extent->length = num;
1914 }
1915 }
1916
1917 extents_end = extent + 1;
1918
1919 for (extent = extents; extent < extents_end; extent++) {
1920 extent->flags = cpu_to_be32(extent->flags);
1921 extent->length = cpu_to_be32(extent->length);
1922 }
1923
1924 *bytes -= remaining_bytes;
1925 *nb_extents = extents_end - extents;
1926
1927 return 0;
1928 }
1929
1930 /* nbd_co_send_extents
1931 *
1932 * @length is only for tracing purposes (and may be smaller or larger
1933 * than the client's original request). @last controls whether
1934 * NBD_REPLY_FLAG_DONE is sent. @extents should already be in
1935 * big-endian format.
1936 */
1937 static int nbd_co_send_extents(NBDClient *client, uint64_t handle,
1938 NBDExtent *extents, unsigned int nb_extents,
1939 uint64_t length, bool last,
1940 uint32_t context_id, Error **errp)
1941 {
1942 NBDStructuredMeta chunk;
1943
1944 struct iovec iov[] = {
1945 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1946 {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])}
1947 };
1948
1949 trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last);
1950 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0,
1951 NBD_REPLY_TYPE_BLOCK_STATUS,
1952 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
1953 stl_be_p(&chunk.context_id, context_id);
1954
1955 return nbd_co_send_iov(client, iov, 2, errp);
1956 }
1957
1958 /* Get block status from the exported device and send it to the client */
1959 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle,
1960 BlockDriverState *bs, uint64_t offset,
1961 uint32_t length, bool dont_fragment,
1962 bool last, uint32_t context_id,
1963 Error **errp)
1964 {
1965 int ret;
1966 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS;
1967 NBDExtent *extents = g_new(NBDExtent, nb_extents);
1968 uint64_t final_length = length;
1969
1970 ret = blockstatus_to_extents(bs, offset, &final_length, extents,
1971 &nb_extents);
1972 if (ret < 0) {
1973 g_free(extents);
1974 return nbd_co_send_structured_error(
1975 client, handle, -ret, "can't get block status", errp);
1976 }
1977
1978 ret = nbd_co_send_extents(client, handle, extents, nb_extents,
1979 final_length, last, context_id, errp);
1980
1981 g_free(extents);
1982
1983 return ret;
1984 }
1985
1986 /*
1987 * Populate @extents from a dirty bitmap. Unless @dont_fragment, the
1988 * final extent may exceed the original @length. Store in @length the
1989 * byte length encoded (which may be smaller or larger than the
1990 * original), and return the number of extents used.
1991 */
1992 static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset,
1993 uint64_t *length, NBDExtent *extents,
1994 unsigned int nb_extents,
1995 bool dont_fragment)
1996 {
1997 uint64_t begin = offset, end = offset;
1998 uint64_t overall_end = offset + *length;
1999 unsigned int i = 0;
2000 BdrvDirtyBitmapIter *it;
2001 bool dirty;
2002
2003 bdrv_dirty_bitmap_lock(bitmap);
2004
2005 it = bdrv_dirty_iter_new(bitmap);
2006 dirty = bdrv_get_dirty_locked(NULL, bitmap, offset);
2007
2008 assert(begin < overall_end && nb_extents);
2009 while (begin < overall_end && i < nb_extents) {
2010 bool next_dirty = !dirty;
2011
2012 if (dirty) {
2013 end = bdrv_dirty_bitmap_next_zero(bitmap, begin, UINT64_MAX);
2014 } else {
2015 bdrv_set_dirty_iter(it, begin);
2016 end = bdrv_dirty_iter_next(it);
2017 }
2018 if (end == -1 || end - begin > UINT32_MAX) {
2019 /* Cap to an aligned value < 4G beyond begin. */
2020 end = MIN(bdrv_dirty_bitmap_size(bitmap),
2021 begin + UINT32_MAX + 1 -
2022 bdrv_dirty_bitmap_granularity(bitmap));
2023 next_dirty = dirty;
2024 }
2025 if (dont_fragment && end > overall_end) {
2026 end = overall_end;
2027 }
2028
2029 extents[i].length = cpu_to_be32(end - begin);
2030 extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0);
2031 i++;
2032 begin = end;
2033 dirty = next_dirty;
2034 }
2035
2036 bdrv_dirty_iter_free(it);
2037
2038 bdrv_dirty_bitmap_unlock(bitmap);
2039
2040 assert(offset < end);
2041 *length = end - offset;
2042 return i;
2043 }
2044
2045 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle,
2046 BdrvDirtyBitmap *bitmap, uint64_t offset,
2047 uint32_t length, bool dont_fragment, bool last,
2048 uint32_t context_id, Error **errp)
2049 {
2050 int ret;
2051 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS;
2052 NBDExtent *extents = g_new(NBDExtent, nb_extents);
2053 uint64_t final_length = length;
2054
2055 nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents,
2056 nb_extents, dont_fragment);
2057
2058 ret = nbd_co_send_extents(client, handle, extents, nb_extents,
2059 final_length, last, context_id, errp);
2060
2061 g_free(extents);
2062
2063 return ret;
2064 }
2065
2066 /* nbd_co_receive_request
2067 * Collect a client request. Return 0 if request looks valid, -EIO to drop
2068 * connection right away, and any other negative value to report an error to
2069 * the client (although the caller may still need to disconnect after reporting
2070 * the error).
2071 */
2072 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,
2073 Error **errp)
2074 {
2075 NBDClient *client = req->client;
2076 int valid_flags;
2077
2078 g_assert(qemu_in_coroutine());
2079 assert(client->recv_coroutine == qemu_coroutine_self());
2080 if (nbd_receive_request(client->ioc, request, errp) < 0) {
2081 return -EIO;
2082 }
2083
2084 trace_nbd_co_receive_request_decode_type(request->handle, request->type,
2085 nbd_cmd_lookup(request->type));
2086
2087 if (request->type != NBD_CMD_WRITE) {
2088 /* No payload, we are ready to read the next request. */
2089 req->complete = true;
2090 }
2091
2092 if (request->type == NBD_CMD_DISC) {
2093 /* Special case: we're going to disconnect without a reply,
2094 * whether or not flags, from, or len are bogus */
2095 return -EIO;
2096 }
2097
2098 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE ||
2099 request->type == NBD_CMD_CACHE)
2100 {
2101 if (request->len > NBD_MAX_BUFFER_SIZE) {
2102 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
2103 request->len, NBD_MAX_BUFFER_SIZE);
2104 return -EINVAL;
2105 }
2106
2107 req->data = blk_try_blockalign(client->exp->blk, request->len);
2108 if (req->data == NULL) {
2109 error_setg(errp, "No memory");
2110 return -ENOMEM;
2111 }
2112 }
2113 if (request->type == NBD_CMD_WRITE) {
2114 if (nbd_read(client->ioc, req->data, request->len, errp) < 0) {
2115 error_prepend(errp, "reading from socket failed: ");
2116 return -EIO;
2117 }
2118 req->complete = true;
2119
2120 trace_nbd_co_receive_request_payload_received(request->handle,
2121 request->len);
2122 }
2123
2124 /* Sanity checks. */
2125 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY &&
2126 (request->type == NBD_CMD_WRITE ||
2127 request->type == NBD_CMD_WRITE_ZEROES ||
2128 request->type == NBD_CMD_TRIM)) {
2129 error_setg(errp, "Export is read-only");
2130 return -EROFS;
2131 }
2132 if (request->from > client->exp->size ||
2133 request->len > client->exp->size - request->from) {
2134 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32
2135 ", Size: %" PRIu64, request->from, request->len,
2136 client->exp->size);
2137 return (request->type == NBD_CMD_WRITE ||
2138 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL;
2139 }
2140 valid_flags = NBD_CMD_FLAG_FUA;
2141 if (request->type == NBD_CMD_READ && client->structured_reply) {
2142 valid_flags |= NBD_CMD_FLAG_DF;
2143 } else if (request->type == NBD_CMD_WRITE_ZEROES) {
2144 valid_flags |= NBD_CMD_FLAG_NO_HOLE;
2145 } else if (request->type == NBD_CMD_BLOCK_STATUS) {
2146 valid_flags |= NBD_CMD_FLAG_REQ_ONE;
2147 }
2148 if (request->flags & ~valid_flags) {
2149 error_setg(errp, "unsupported flags for command %s (got 0x%x)",
2150 nbd_cmd_lookup(request->type), request->flags);
2151 return -EINVAL;
2152 }
2153
2154 return 0;
2155 }
2156
2157 /* Send simple reply without a payload, or a structured error
2158 * @error_msg is ignored if @ret >= 0
2159 * Returns 0 if connection is still live, -errno on failure to talk to client
2160 */
2161 static coroutine_fn int nbd_send_generic_reply(NBDClient *client,
2162 uint64_t handle,
2163 int ret,
2164 const char *error_msg,
2165 Error **errp)
2166 {
2167 if (client->structured_reply && ret < 0) {
2168 return nbd_co_send_structured_error(client, handle, -ret, error_msg,
2169 errp);
2170 } else {
2171 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0,
2172 NULL, 0, errp);
2173 }
2174 }
2175
2176 /* Handle NBD_CMD_READ request.
2177 * Return -errno if sending fails. Other errors are reported directly to the
2178 * client as an error reply. */
2179 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request,
2180 uint8_t *data, Error **errp)
2181 {
2182 int ret;
2183 NBDExport *exp = client->exp;
2184
2185 assert(request->type == NBD_CMD_READ || request->type == NBD_CMD_CACHE);
2186
2187 /* XXX: NBD Protocol only documents use of FUA with WRITE */
2188 if (request->flags & NBD_CMD_FLAG_FUA) {
2189 ret = blk_co_flush(exp->blk);
2190 if (ret < 0) {
2191 return nbd_send_generic_reply(client, request->handle, ret,
2192 "flush failed", errp);
2193 }
2194 }
2195
2196 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) &&
2197 request->len && request->type != NBD_CMD_CACHE)
2198 {
2199 return nbd_co_send_sparse_read(client, request->handle, request->from,
2200 data, request->len, errp);
2201 }
2202
2203 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data,
2204 request->len);
2205 if (ret < 0 || request->type == NBD_CMD_CACHE) {
2206 return nbd_send_generic_reply(client, request->handle, ret,
2207 "reading from file failed", errp);
2208 }
2209
2210 if (client->structured_reply) {
2211 if (request->len) {
2212 return nbd_co_send_structured_read(client, request->handle,
2213 request->from, data,
2214 request->len, true, errp);
2215 } else {
2216 return nbd_co_send_structured_done(client, request->handle, errp);
2217 }
2218 } else {
2219 return nbd_co_send_simple_reply(client, request->handle, 0,
2220 data, request->len, errp);
2221 }
2222 }
2223
2224 /* Handle NBD request.
2225 * Return -errno if sending fails. Other errors are reported directly to the
2226 * client as an error reply. */
2227 static coroutine_fn int nbd_handle_request(NBDClient *client,
2228 NBDRequest *request,
2229 uint8_t *data, Error **errp)
2230 {
2231 int ret;
2232 int flags;
2233 NBDExport *exp = client->exp;
2234 char *msg;
2235
2236 switch (request->type) {
2237 case NBD_CMD_READ:
2238 case NBD_CMD_CACHE:
2239 return nbd_do_cmd_read(client, request, data, errp);
2240
2241 case NBD_CMD_WRITE:
2242 flags = 0;
2243 if (request->flags & NBD_CMD_FLAG_FUA) {
2244 flags |= BDRV_REQ_FUA;
2245 }
2246 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset,
2247 data, request->len, flags);
2248 return nbd_send_generic_reply(client, request->handle, ret,
2249 "writing to file failed", errp);
2250
2251 case NBD_CMD_WRITE_ZEROES:
2252 flags = 0;
2253 if (request->flags & NBD_CMD_FLAG_FUA) {
2254 flags |= BDRV_REQ_FUA;
2255 }
2256 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) {
2257 flags |= BDRV_REQ_MAY_UNMAP;
2258 }
2259 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset,
2260 request->len, flags);
2261 return nbd_send_generic_reply(client, request->handle, ret,
2262 "writing to file failed", errp);
2263
2264 case NBD_CMD_DISC:
2265 /* unreachable, thanks to special case in nbd_co_receive_request() */
2266 abort();
2267
2268 case NBD_CMD_FLUSH:
2269 ret = blk_co_flush(exp->blk);
2270 return nbd_send_generic_reply(client, request->handle, ret,
2271 "flush failed", errp);
2272
2273 case NBD_CMD_TRIM:
2274 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset,
2275 request->len);
2276 if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) {
2277 ret = blk_co_flush(exp->blk);
2278 }
2279 return nbd_send_generic_reply(client, request->handle, ret,
2280 "discard failed", errp);
2281
2282 case NBD_CMD_BLOCK_STATUS:
2283 if (!request->len) {
2284 return nbd_send_generic_reply(client, request->handle, -EINVAL,
2285 "need non-zero length", errp);
2286 }
2287 if (client->export_meta.valid &&
2288 (client->export_meta.base_allocation ||
2289 client->export_meta.bitmap))
2290 {
2291 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE;
2292
2293 if (client->export_meta.base_allocation) {
2294 ret = nbd_co_send_block_status(client, request->handle,
2295 blk_bs(exp->blk), request->from,
2296 request->len, dont_fragment,
2297 !client->export_meta.bitmap,
2298 NBD_META_ID_BASE_ALLOCATION,
2299 errp);
2300 if (ret < 0) {
2301 return ret;
2302 }
2303 }
2304
2305 if (client->export_meta.bitmap) {
2306 ret = nbd_co_send_bitmap(client, request->handle,
2307 client->exp->export_bitmap,
2308 request->from, request->len,
2309 dont_fragment,
2310 true, NBD_META_ID_DIRTY_BITMAP, errp);
2311 if (ret < 0) {
2312 return ret;
2313 }
2314 }
2315
2316 return ret;
2317 } else {
2318 return nbd_send_generic_reply(client, request->handle, -EINVAL,
2319 "CMD_BLOCK_STATUS not negotiated",
2320 errp);
2321 }
2322
2323 default:
2324 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received",
2325 request->type);
2326 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg,
2327 errp);
2328 g_free(msg);
2329 return ret;
2330 }
2331 }
2332
2333 /* Owns a reference to the NBDClient passed as opaque. */
2334 static coroutine_fn void nbd_trip(void *opaque)
2335 {
2336 NBDClient *client = opaque;
2337 NBDRequestData *req;
2338 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */
2339 int ret;
2340 Error *local_err = NULL;
2341
2342 trace_nbd_trip();
2343 if (client->closing) {
2344 nbd_client_put(client);
2345 return;
2346 }
2347
2348 req = nbd_request_get(client);
2349 ret = nbd_co_receive_request(req, &request, &local_err);
2350 client->recv_coroutine = NULL;
2351
2352 if (client->closing) {
2353 /*
2354 * The client may be closed when we are blocked in
2355 * nbd_co_receive_request()
2356 */
2357 goto done;
2358 }
2359
2360 nbd_client_receive_next_request(client);
2361 if (ret == -EIO) {
2362 goto disconnect;
2363 }
2364
2365 if (ret < 0) {
2366 /* It wans't -EIO, so, according to nbd_co_receive_request()
2367 * semantics, we should return the error to the client. */
2368 Error *export_err = local_err;
2369
2370 local_err = NULL;
2371 ret = nbd_send_generic_reply(client, request.handle, -EINVAL,
2372 error_get_pretty(export_err), &local_err);
2373 error_free(export_err);
2374 } else {
2375 ret = nbd_handle_request(client, &request, req->data, &local_err);
2376 }
2377 if (ret < 0) {
2378 error_prepend(&local_err, "Failed to send reply: ");
2379 goto disconnect;
2380 }
2381
2382 /* We must disconnect after NBD_CMD_WRITE if we did not
2383 * read the payload.
2384 */
2385 if (!req->complete) {
2386 error_setg(&local_err, "Request handling failed in intermediate state");
2387 goto disconnect;
2388 }
2389
2390 done:
2391 nbd_request_put(req);
2392 nbd_client_put(client);
2393 return;
2394
2395 disconnect:
2396 if (local_err) {
2397 error_reportf_err(local_err, "Disconnect client, due to: ");
2398 }
2399 nbd_request_put(req);
2400 client_close(client, true);
2401 nbd_client_put(client);
2402 }
2403
2404 static void nbd_client_receive_next_request(NBDClient *client)
2405 {
2406 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) {
2407 nbd_client_get(client);
2408 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
2409 aio_co_schedule(client->exp->ctx, client->recv_coroutine);
2410 }
2411 }
2412
2413 static coroutine_fn void nbd_co_client_start(void *opaque)
2414 {
2415 NBDClient *client = opaque;
2416 Error *local_err = NULL;
2417
2418 qemu_co_mutex_init(&client->send_lock);
2419
2420 if (nbd_negotiate(client, &local_err)) {
2421 if (local_err) {
2422 error_report_err(local_err);
2423 }
2424 client_close(client, false);
2425 return;
2426 }
2427
2428 nbd_client_receive_next_request(client);
2429 }
2430
2431 /*
2432 * Create a new client listener using the given channel @sioc.
2433 * Begin servicing it in a coroutine. When the connection closes, call
2434 * @close_fn with an indication of whether the client completed negotiation.
2435 */
2436 void nbd_client_new(QIOChannelSocket *sioc,
2437 QCryptoTLSCreds *tlscreds,
2438 const char *tlsaclname,
2439 void (*close_fn)(NBDClient *, bool))
2440 {
2441 NBDClient *client;
2442 Coroutine *co;
2443
2444 client = g_new0(NBDClient, 1);
2445 client->refcount = 1;
2446 client->tlscreds = tlscreds;
2447 if (tlscreds) {
2448 object_ref(OBJECT(client->tlscreds));
2449 }
2450 client->tlsaclname = g_strdup(tlsaclname);
2451 client->sioc = sioc;
2452 object_ref(OBJECT(client->sioc));
2453 client->ioc = QIO_CHANNEL(sioc);
2454 object_ref(OBJECT(client->ioc));
2455 client->close_fn = close_fn;
2456
2457 co = qemu_coroutine_create(nbd_co_client_start, client);
2458 qemu_coroutine_enter(co);
2459 }
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