nbd/client: Add x-dirty-bitmap to query bitmap from server
[qemu.git] / nbd / client.c
1 /*
2 * Copyright (C) 2016-2018 Red Hat, Inc.
3 * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
4 *
5 * Network Block Device Client 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 /* Definitions for opaque data types */
26
27 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
28
29 /* That's all folks */
30
31 /* Basic flow for negotiation
32
33 Server Client
34 Negotiate
35
36 or
37
38 Server Client
39 Negotiate #1
40 Option
41 Negotiate #2
42
43 ----
44
45 followed by
46
47 Server Client
48 Request
49 Response
50 Request
51 Response
52 ...
53 ...
54 Request (type == 2)
55
56 */
57
58 /* Send an option request.
59 *
60 * The request is for option @opt, with @data containing @len bytes of
61 * additional payload for the request (@len may be -1 to treat @data as
62 * a C string; and @data may be NULL if @len is 0).
63 * Return 0 if successful, -1 with errp set if it is impossible to
64 * continue. */
65 static int nbd_send_option_request(QIOChannel *ioc, uint32_t opt,
66 uint32_t len, const char *data,
67 Error **errp)
68 {
69 NBDOption req;
70 QEMU_BUILD_BUG_ON(sizeof(req) != 16);
71
72 if (len == -1) {
73 req.length = len = strlen(data);
74 }
75 trace_nbd_send_option_request(opt, nbd_opt_lookup(opt), len);
76
77 stq_be_p(&req.magic, NBD_OPTS_MAGIC);
78 stl_be_p(&req.option, opt);
79 stl_be_p(&req.length, len);
80
81 if (nbd_write(ioc, &req, sizeof(req), errp) < 0) {
82 error_prepend(errp, "Failed to send option request header: ");
83 return -1;
84 }
85
86 if (len && nbd_write(ioc, (char *) data, len, errp) < 0) {
87 error_prepend(errp, "Failed to send option request data: ");
88 return -1;
89 }
90
91 return 0;
92 }
93
94 /* Send NBD_OPT_ABORT as a courtesy to let the server know that we are
95 * not going to attempt further negotiation. */
96 static void nbd_send_opt_abort(QIOChannel *ioc)
97 {
98 /* Technically, a compliant server is supposed to reply to us; but
99 * older servers disconnected instead. At any rate, we're allowed
100 * to disconnect without waiting for the server reply, so we don't
101 * even care if the request makes it to the server, let alone
102 * waiting around for whether the server replies. */
103 nbd_send_option_request(ioc, NBD_OPT_ABORT, 0, NULL, NULL);
104 }
105
106
107 /* Receive the header of an option reply, which should match the given
108 * opt. Read through the length field, but NOT the length bytes of
109 * payload. Return 0 if successful, -1 with errp set if it is
110 * impossible to continue. */
111 static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt,
112 NBDOptionReply *reply, Error **errp)
113 {
114 QEMU_BUILD_BUG_ON(sizeof(*reply) != 20);
115 if (nbd_read(ioc, reply, sizeof(*reply), errp) < 0) {
116 error_prepend(errp, "failed to read option reply: ");
117 nbd_send_opt_abort(ioc);
118 return -1;
119 }
120 be64_to_cpus(&reply->magic);
121 be32_to_cpus(&reply->option);
122 be32_to_cpus(&reply->type);
123 be32_to_cpus(&reply->length);
124
125 trace_nbd_receive_option_reply(reply->option, nbd_opt_lookup(reply->option),
126 reply->type, nbd_rep_lookup(reply->type),
127 reply->length);
128
129 if (reply->magic != NBD_REP_MAGIC) {
130 error_setg(errp, "Unexpected option reply magic");
131 nbd_send_opt_abort(ioc);
132 return -1;
133 }
134 if (reply->option != opt) {
135 error_setg(errp, "Unexpected option type %x expected %x",
136 reply->option, opt);
137 nbd_send_opt_abort(ioc);
138 return -1;
139 }
140 return 0;
141 }
142
143 /* If reply represents success, return 1 without further action.
144 * If reply represents an error, consume the optional payload of
145 * the packet on ioc. Then return 0 for unsupported (so the client
146 * can fall back to other approaches), or -1 with errp set for other
147 * errors.
148 */
149 static int nbd_handle_reply_err(QIOChannel *ioc, NBDOptionReply *reply,
150 Error **errp)
151 {
152 char *msg = NULL;
153 int result = -1;
154
155 if (!(reply->type & (1 << 31))) {
156 return 1;
157 }
158
159 if (reply->length) {
160 if (reply->length > NBD_MAX_BUFFER_SIZE) {
161 error_setg(errp, "server error %" PRIu32
162 " (%s) message is too long",
163 reply->type, nbd_rep_lookup(reply->type));
164 goto cleanup;
165 }
166 msg = g_malloc(reply->length + 1);
167 if (nbd_read(ioc, msg, reply->length, errp) < 0) {
168 error_prepend(errp, "failed to read option error %" PRIu32
169 " (%s) message: ",
170 reply->type, nbd_rep_lookup(reply->type));
171 goto cleanup;
172 }
173 msg[reply->length] = '\0';
174 }
175
176 switch (reply->type) {
177 case NBD_REP_ERR_UNSUP:
178 trace_nbd_reply_err_unsup(reply->option, nbd_opt_lookup(reply->option));
179 result = 0;
180 goto cleanup;
181
182 case NBD_REP_ERR_POLICY:
183 error_setg(errp, "Denied by server for option %" PRIu32 " (%s)",
184 reply->option, nbd_opt_lookup(reply->option));
185 break;
186
187 case NBD_REP_ERR_INVALID:
188 error_setg(errp, "Invalid parameters for option %" PRIu32 " (%s)",
189 reply->option, nbd_opt_lookup(reply->option));
190 break;
191
192 case NBD_REP_ERR_PLATFORM:
193 error_setg(errp, "Server lacks support for option %" PRIu32 " (%s)",
194 reply->option, nbd_opt_lookup(reply->option));
195 break;
196
197 case NBD_REP_ERR_TLS_REQD:
198 error_setg(errp, "TLS negotiation required before option %" PRIu32
199 " (%s)", reply->option, nbd_opt_lookup(reply->option));
200 break;
201
202 case NBD_REP_ERR_UNKNOWN:
203 error_setg(errp, "Requested export not available");
204 break;
205
206 case NBD_REP_ERR_SHUTDOWN:
207 error_setg(errp, "Server shutting down before option %" PRIu32 " (%s)",
208 reply->option, nbd_opt_lookup(reply->option));
209 break;
210
211 case NBD_REP_ERR_BLOCK_SIZE_REQD:
212 error_setg(errp, "Server requires INFO_BLOCK_SIZE for option %" PRIu32
213 " (%s)", reply->option, nbd_opt_lookup(reply->option));
214 break;
215
216 default:
217 error_setg(errp, "Unknown error code when asking for option %" PRIu32
218 " (%s)", reply->option, nbd_opt_lookup(reply->option));
219 break;
220 }
221
222 if (msg) {
223 error_append_hint(errp, "server reported: %s\n", msg);
224 }
225
226 cleanup:
227 g_free(msg);
228 if (result < 0) {
229 nbd_send_opt_abort(ioc);
230 }
231 return result;
232 }
233
234 /* Process another portion of the NBD_OPT_LIST reply. Set *@match if
235 * the current reply matches @want or if the server does not support
236 * NBD_OPT_LIST, otherwise leave @match alone. Return 0 if iteration
237 * is complete, positive if more replies are expected, or negative
238 * with @errp set if an unrecoverable error occurred. */
239 static int nbd_receive_list(QIOChannel *ioc, const char *want, bool *match,
240 Error **errp)
241 {
242 NBDOptionReply reply;
243 uint32_t len;
244 uint32_t namelen;
245 char name[NBD_MAX_NAME_SIZE + 1];
246 int error;
247
248 if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) {
249 return -1;
250 }
251 error = nbd_handle_reply_err(ioc, &reply, errp);
252 if (error <= 0) {
253 /* The server did not support NBD_OPT_LIST, so set *match on
254 * the assumption that any name will be accepted. */
255 *match = true;
256 return error;
257 }
258 len = reply.length;
259
260 if (reply.type == NBD_REP_ACK) {
261 if (len != 0) {
262 error_setg(errp, "length too long for option end");
263 nbd_send_opt_abort(ioc);
264 return -1;
265 }
266 return 0;
267 } else if (reply.type != NBD_REP_SERVER) {
268 error_setg(errp, "Unexpected reply type %" PRIx32 " expected %x",
269 reply.type, NBD_REP_SERVER);
270 nbd_send_opt_abort(ioc);
271 return -1;
272 }
273
274 if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) {
275 error_setg(errp, "incorrect option length %" PRIu32, len);
276 nbd_send_opt_abort(ioc);
277 return -1;
278 }
279 if (nbd_read(ioc, &namelen, sizeof(namelen), errp) < 0) {
280 error_prepend(errp, "failed to read option name length: ");
281 nbd_send_opt_abort(ioc);
282 return -1;
283 }
284 namelen = be32_to_cpu(namelen);
285 len -= sizeof(namelen);
286 if (len < namelen) {
287 error_setg(errp, "incorrect option name length");
288 nbd_send_opt_abort(ioc);
289 return -1;
290 }
291 if (namelen != strlen(want)) {
292 if (nbd_drop(ioc, len, errp) < 0) {
293 error_prepend(errp,
294 "failed to skip export name with wrong length: ");
295 nbd_send_opt_abort(ioc);
296 return -1;
297 }
298 return 1;
299 }
300
301 assert(namelen < sizeof(name));
302 if (nbd_read(ioc, name, namelen, errp) < 0) {
303 error_prepend(errp, "failed to read export name: ");
304 nbd_send_opt_abort(ioc);
305 return -1;
306 }
307 name[namelen] = '\0';
308 len -= namelen;
309 if (nbd_drop(ioc, len, errp) < 0) {
310 error_prepend(errp, "failed to read export description: ");
311 nbd_send_opt_abort(ioc);
312 return -1;
313 }
314 if (!strcmp(name, want)) {
315 *match = true;
316 }
317 return 1;
318 }
319
320
321 /* Returns -1 if NBD_OPT_GO proves the export @wantname cannot be
322 * used, 0 if NBD_OPT_GO is unsupported (fall back to NBD_OPT_LIST and
323 * NBD_OPT_EXPORT_NAME in that case), and > 0 if the export is good to
324 * go (with @info populated). */
325 static int nbd_opt_go(QIOChannel *ioc, const char *wantname,
326 NBDExportInfo *info, Error **errp)
327 {
328 NBDOptionReply reply;
329 uint32_t len = strlen(wantname);
330 uint16_t type;
331 int error;
332 char *buf;
333
334 /* The protocol requires that the server send NBD_INFO_EXPORT with
335 * a non-zero flags (at least NBD_FLAG_HAS_FLAGS must be set); so
336 * flags still 0 is a witness of a broken server. */
337 info->flags = 0;
338
339 trace_nbd_opt_go_start(wantname);
340 buf = g_malloc(4 + len + 2 + 2 * info->request_sizes + 1);
341 stl_be_p(buf, len);
342 memcpy(buf + 4, wantname, len);
343 /* At most one request, everything else up to server */
344 stw_be_p(buf + 4 + len, info->request_sizes);
345 if (info->request_sizes) {
346 stw_be_p(buf + 4 + len + 2, NBD_INFO_BLOCK_SIZE);
347 }
348 error = nbd_send_option_request(ioc, NBD_OPT_GO,
349 4 + len + 2 + 2 * info->request_sizes,
350 buf, errp);
351 g_free(buf);
352 if (error < 0) {
353 return -1;
354 }
355
356 while (1) {
357 if (nbd_receive_option_reply(ioc, NBD_OPT_GO, &reply, errp) < 0) {
358 return -1;
359 }
360 error = nbd_handle_reply_err(ioc, &reply, errp);
361 if (error <= 0) {
362 return error;
363 }
364 len = reply.length;
365
366 if (reply.type == NBD_REP_ACK) {
367 /* Server is done sending info and moved into transmission
368 phase, but make sure it sent flags */
369 if (len) {
370 error_setg(errp, "server sent invalid NBD_REP_ACK");
371 return -1;
372 }
373 if (!info->flags) {
374 error_setg(errp, "broken server omitted NBD_INFO_EXPORT");
375 return -1;
376 }
377 trace_nbd_opt_go_success();
378 return 1;
379 }
380 if (reply.type != NBD_REP_INFO) {
381 error_setg(errp, "unexpected reply type %" PRIu32
382 " (%s), expected %u",
383 reply.type, nbd_rep_lookup(reply.type), NBD_REP_INFO);
384 nbd_send_opt_abort(ioc);
385 return -1;
386 }
387 if (len < sizeof(type)) {
388 error_setg(errp, "NBD_REP_INFO length %" PRIu32 " is too short",
389 len);
390 nbd_send_opt_abort(ioc);
391 return -1;
392 }
393 if (nbd_read(ioc, &type, sizeof(type), errp) < 0) {
394 error_prepend(errp, "failed to read info type: ");
395 nbd_send_opt_abort(ioc);
396 return -1;
397 }
398 len -= sizeof(type);
399 be16_to_cpus(&type);
400 switch (type) {
401 case NBD_INFO_EXPORT:
402 if (len != sizeof(info->size) + sizeof(info->flags)) {
403 error_setg(errp, "remaining export info len %" PRIu32
404 " is unexpected size", len);
405 nbd_send_opt_abort(ioc);
406 return -1;
407 }
408 if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {
409 error_prepend(errp, "failed to read info size: ");
410 nbd_send_opt_abort(ioc);
411 return -1;
412 }
413 be64_to_cpus(&info->size);
414 if (nbd_read(ioc, &info->flags, sizeof(info->flags), errp) < 0) {
415 error_prepend(errp, "failed to read info flags: ");
416 nbd_send_opt_abort(ioc);
417 return -1;
418 }
419 be16_to_cpus(&info->flags);
420 trace_nbd_receive_negotiate_size_flags(info->size, info->flags);
421 break;
422
423 case NBD_INFO_BLOCK_SIZE:
424 if (len != sizeof(info->min_block) * 3) {
425 error_setg(errp, "remaining export info len %" PRIu32
426 " is unexpected size", len);
427 nbd_send_opt_abort(ioc);
428 return -1;
429 }
430 if (nbd_read(ioc, &info->min_block, sizeof(info->min_block),
431 errp) < 0) {
432 error_prepend(errp, "failed to read info minimum block size: ");
433 nbd_send_opt_abort(ioc);
434 return -1;
435 }
436 be32_to_cpus(&info->min_block);
437 if (!is_power_of_2(info->min_block)) {
438 error_setg(errp, "server minimum block size %" PRIu32
439 " is not a power of two", info->min_block);
440 nbd_send_opt_abort(ioc);
441 return -1;
442 }
443 if (nbd_read(ioc, &info->opt_block, sizeof(info->opt_block),
444 errp) < 0) {
445 error_prepend(errp,
446 "failed to read info preferred block size: ");
447 nbd_send_opt_abort(ioc);
448 return -1;
449 }
450 be32_to_cpus(&info->opt_block);
451 if (!is_power_of_2(info->opt_block) ||
452 info->opt_block < info->min_block) {
453 error_setg(errp, "server preferred block size %" PRIu32
454 " is not valid", info->opt_block);
455 nbd_send_opt_abort(ioc);
456 return -1;
457 }
458 if (nbd_read(ioc, &info->max_block, sizeof(info->max_block),
459 errp) < 0) {
460 error_prepend(errp, "failed to read info maximum block size: ");
461 nbd_send_opt_abort(ioc);
462 return -1;
463 }
464 be32_to_cpus(&info->max_block);
465 if (info->max_block < info->min_block) {
466 error_setg(errp, "server maximum block size %" PRIu32
467 " is not valid", info->max_block);
468 nbd_send_opt_abort(ioc);
469 return -1;
470 }
471 trace_nbd_opt_go_info_block_size(info->min_block, info->opt_block,
472 info->max_block);
473 break;
474
475 default:
476 trace_nbd_opt_go_info_unknown(type, nbd_info_lookup(type));
477 if (nbd_drop(ioc, len, errp) < 0) {
478 error_prepend(errp, "Failed to read info payload: ");
479 nbd_send_opt_abort(ioc);
480 return -1;
481 }
482 break;
483 }
484 }
485 }
486
487 /* Return -1 on failure, 0 if wantname is an available export. */
488 static int nbd_receive_query_exports(QIOChannel *ioc,
489 const char *wantname,
490 Error **errp)
491 {
492 bool foundExport = false;
493
494 trace_nbd_receive_query_exports_start(wantname);
495 if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) {
496 return -1;
497 }
498
499 while (1) {
500 int ret = nbd_receive_list(ioc, wantname, &foundExport, errp);
501
502 if (ret < 0) {
503 /* Server gave unexpected reply */
504 return -1;
505 } else if (ret == 0) {
506 /* Done iterating. */
507 if (!foundExport) {
508 error_setg(errp, "No export with name '%s' available",
509 wantname);
510 nbd_send_opt_abort(ioc);
511 return -1;
512 }
513 trace_nbd_receive_query_exports_success(wantname);
514 return 0;
515 }
516 }
517 }
518
519 /* nbd_request_simple_option: Send an option request, and parse the reply
520 * return 1 for successful negotiation,
521 * 0 if operation is unsupported,
522 * -1 with errp set for any other error
523 */
524 static int nbd_request_simple_option(QIOChannel *ioc, int opt, Error **errp)
525 {
526 NBDOptionReply reply;
527 int error;
528
529 if (nbd_send_option_request(ioc, opt, 0, NULL, errp) < 0) {
530 return -1;
531 }
532
533 if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) {
534 return -1;
535 }
536 error = nbd_handle_reply_err(ioc, &reply, errp);
537 if (error <= 0) {
538 return error;
539 }
540
541 if (reply.type != NBD_REP_ACK) {
542 error_setg(errp, "Server answered option %d (%s) with unexpected "
543 "reply %" PRIu32 " (%s)", opt, nbd_opt_lookup(opt),
544 reply.type, nbd_rep_lookup(reply.type));
545 nbd_send_opt_abort(ioc);
546 return -1;
547 }
548
549 if (reply.length != 0) {
550 error_setg(errp, "Option %d ('%s') response length is %" PRIu32
551 " (it should be zero)", opt, nbd_opt_lookup(opt),
552 reply.length);
553 nbd_send_opt_abort(ioc);
554 return -1;
555 }
556
557 return 1;
558 }
559
560 static QIOChannel *nbd_receive_starttls(QIOChannel *ioc,
561 QCryptoTLSCreds *tlscreds,
562 const char *hostname, Error **errp)
563 {
564 int ret;
565 QIOChannelTLS *tioc;
566 struct NBDTLSHandshakeData data = { 0 };
567
568 ret = nbd_request_simple_option(ioc, NBD_OPT_STARTTLS, errp);
569 if (ret <= 0) {
570 if (ret == 0) {
571 error_setg(errp, "Server don't support STARTTLS option");
572 nbd_send_opt_abort(ioc);
573 }
574 return NULL;
575 }
576
577 trace_nbd_receive_starttls_new_client();
578 tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp);
579 if (!tioc) {
580 return NULL;
581 }
582 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-client-tls");
583 data.loop = g_main_loop_new(g_main_context_default(), FALSE);
584 trace_nbd_receive_starttls_tls_handshake();
585 qio_channel_tls_handshake(tioc,
586 nbd_tls_handshake,
587 &data,
588 NULL,
589 NULL);
590
591 if (!data.complete) {
592 g_main_loop_run(data.loop);
593 }
594 g_main_loop_unref(data.loop);
595 if (data.error) {
596 error_propagate(errp, data.error);
597 object_unref(OBJECT(tioc));
598 return NULL;
599 }
600
601 return QIO_CHANNEL(tioc);
602 }
603
604 /* nbd_negotiate_simple_meta_context:
605 * Set one meta context. Simple means that reply must contain zero (not
606 * negotiated) or one (negotiated) contexts. More contexts would be considered
607 * as a protocol error. It's also implied that meta-data query equals queried
608 * context name, so, if server replies with something different than @context,
609 * it is considered an error too.
610 * return 1 for successful negotiation, context_id is set
611 * 0 if operation is unsupported,
612 * -1 with errp set for any other error
613 */
614 static int nbd_negotiate_simple_meta_context(QIOChannel *ioc,
615 const char *export,
616 const char *context,
617 uint32_t *context_id,
618 Error **errp)
619 {
620 int ret;
621 NBDOptionReply reply;
622 uint32_t received_id = 0;
623 bool received = false;
624 uint32_t export_len = strlen(export);
625 uint32_t context_len = strlen(context);
626 uint32_t data_len = sizeof(export_len) + export_len +
627 sizeof(uint32_t) + /* number of queries */
628 sizeof(context_len) + context_len;
629 char *data = g_malloc(data_len);
630 char *p = data;
631
632 trace_nbd_opt_meta_request(context, export);
633 stl_be_p(p, export_len);
634 memcpy(p += sizeof(export_len), export, export_len);
635 stl_be_p(p += export_len, 1);
636 stl_be_p(p += sizeof(uint32_t), context_len);
637 memcpy(p += sizeof(context_len), context, context_len);
638
639 ret = nbd_send_option_request(ioc, NBD_OPT_SET_META_CONTEXT, data_len, data,
640 errp);
641 g_free(data);
642 if (ret < 0) {
643 return ret;
644 }
645
646 if (nbd_receive_option_reply(ioc, NBD_OPT_SET_META_CONTEXT, &reply,
647 errp) < 0)
648 {
649 return -1;
650 }
651
652 ret = nbd_handle_reply_err(ioc, &reply, errp);
653 if (ret <= 0) {
654 return ret;
655 }
656
657 if (reply.type == NBD_REP_META_CONTEXT) {
658 char *name;
659
660 if (reply.length != sizeof(received_id) + context_len) {
661 error_setg(errp, "Failed to negotiate meta context '%s', server "
662 "answered with unexpected length %" PRIu32, context,
663 reply.length);
664 nbd_send_opt_abort(ioc);
665 return -1;
666 }
667
668 if (nbd_read(ioc, &received_id, sizeof(received_id), errp) < 0) {
669 return -1;
670 }
671 be32_to_cpus(&received_id);
672
673 reply.length -= sizeof(received_id);
674 name = g_malloc(reply.length + 1);
675 if (nbd_read(ioc, name, reply.length, errp) < 0) {
676 g_free(name);
677 return -1;
678 }
679 name[reply.length] = '\0';
680 if (strcmp(context, name)) {
681 error_setg(errp, "Failed to negotiate meta context '%s', server "
682 "answered with different context '%s'", context,
683 name);
684 g_free(name);
685 nbd_send_opt_abort(ioc);
686 return -1;
687 }
688 g_free(name);
689
690 trace_nbd_opt_meta_reply(context, received_id);
691 received = true;
692
693 /* receive NBD_REP_ACK */
694 if (nbd_receive_option_reply(ioc, NBD_OPT_SET_META_CONTEXT, &reply,
695 errp) < 0)
696 {
697 return -1;
698 }
699
700 ret = nbd_handle_reply_err(ioc, &reply, errp);
701 if (ret <= 0) {
702 return ret;
703 }
704 }
705
706 if (reply.type != NBD_REP_ACK) {
707 error_setg(errp, "Unexpected reply type %" PRIx32 " expected %x",
708 reply.type, NBD_REP_ACK);
709 nbd_send_opt_abort(ioc);
710 return -1;
711 }
712 if (reply.length) {
713 error_setg(errp, "Unexpected length to ACK response");
714 nbd_send_opt_abort(ioc);
715 return -1;
716 }
717
718 if (received) {
719 *context_id = received_id;
720 return 1;
721 }
722
723 return 0;
724 }
725
726 int nbd_receive_negotiate(QIOChannel *ioc, const char *name,
727 QCryptoTLSCreds *tlscreds, const char *hostname,
728 QIOChannel **outioc, NBDExportInfo *info,
729 Error **errp)
730 {
731 char buf[256];
732 uint64_t magic;
733 int rc;
734 bool zeroes = true;
735 bool structured_reply = info->structured_reply;
736 bool base_allocation = info->base_allocation;
737
738 trace_nbd_receive_negotiate(tlscreds, hostname ? hostname : "<null>");
739
740 info->structured_reply = false;
741 info->base_allocation = false;
742 rc = -EINVAL;
743
744 if (outioc) {
745 *outioc = NULL;
746 }
747 if (tlscreds && !outioc) {
748 error_setg(errp, "Output I/O channel required for TLS");
749 goto fail;
750 }
751
752 if (nbd_read(ioc, buf, 8, errp) < 0) {
753 error_prepend(errp, "Failed to read data: ");
754 goto fail;
755 }
756
757 buf[8] = '\0';
758 if (strlen(buf) == 0) {
759 error_setg(errp, "Server connection closed unexpectedly");
760 goto fail;
761 }
762
763 magic = ldq_be_p(buf);
764 trace_nbd_receive_negotiate_magic(magic);
765
766 if (memcmp(buf, "NBDMAGIC", 8) != 0) {
767 error_setg(errp, "Invalid magic received");
768 goto fail;
769 }
770
771 if (nbd_read(ioc, &magic, sizeof(magic), errp) < 0) {
772 error_prepend(errp, "Failed to read magic: ");
773 goto fail;
774 }
775 magic = be64_to_cpu(magic);
776 trace_nbd_receive_negotiate_magic(magic);
777
778 if (magic == NBD_OPTS_MAGIC) {
779 uint32_t clientflags = 0;
780 uint16_t globalflags;
781 bool fixedNewStyle = false;
782
783 if (nbd_read(ioc, &globalflags, sizeof(globalflags), errp) < 0) {
784 error_prepend(errp, "Failed to read server flags: ");
785 goto fail;
786 }
787 globalflags = be16_to_cpu(globalflags);
788 trace_nbd_receive_negotiate_server_flags(globalflags);
789 if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) {
790 fixedNewStyle = true;
791 clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE;
792 }
793 if (globalflags & NBD_FLAG_NO_ZEROES) {
794 zeroes = false;
795 clientflags |= NBD_FLAG_C_NO_ZEROES;
796 }
797 /* client requested flags */
798 clientflags = cpu_to_be32(clientflags);
799 if (nbd_write(ioc, &clientflags, sizeof(clientflags), errp) < 0) {
800 error_prepend(errp, "Failed to send clientflags field: ");
801 goto fail;
802 }
803 if (tlscreds) {
804 if (fixedNewStyle) {
805 *outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp);
806 if (!*outioc) {
807 goto fail;
808 }
809 ioc = *outioc;
810 } else {
811 error_setg(errp, "Server does not support STARTTLS");
812 goto fail;
813 }
814 }
815 if (!name) {
816 trace_nbd_receive_negotiate_default_name();
817 name = "";
818 }
819 if (fixedNewStyle) {
820 int result;
821
822 if (structured_reply) {
823 result = nbd_request_simple_option(ioc,
824 NBD_OPT_STRUCTURED_REPLY,
825 errp);
826 if (result < 0) {
827 goto fail;
828 }
829 info->structured_reply = result == 1;
830 }
831
832 if (info->structured_reply && base_allocation) {
833 result = nbd_negotiate_simple_meta_context(
834 ioc, name, info->x_dirty_bitmap ?: "base:allocation",
835 &info->meta_base_allocation_id, errp);
836 if (result < 0) {
837 goto fail;
838 }
839 info->base_allocation = result == 1;
840 }
841
842 /* Try NBD_OPT_GO first - if it works, we are done (it
843 * also gives us a good message if the server requires
844 * TLS). If it is not available, fall back to
845 * NBD_OPT_LIST for nicer error messages about a missing
846 * export, then use NBD_OPT_EXPORT_NAME. */
847 result = nbd_opt_go(ioc, name, info, errp);
848 if (result < 0) {
849 goto fail;
850 }
851 if (result > 0) {
852 return 0;
853 }
854 /* Check our desired export is present in the
855 * server export list. Since NBD_OPT_EXPORT_NAME
856 * cannot return an error message, running this
857 * query gives us better error reporting if the
858 * export name is not available.
859 */
860 if (nbd_receive_query_exports(ioc, name, errp) < 0) {
861 goto fail;
862 }
863 }
864 /* write the export name request */
865 if (nbd_send_option_request(ioc, NBD_OPT_EXPORT_NAME, -1, name,
866 errp) < 0) {
867 goto fail;
868 }
869
870 /* Read the response */
871 if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {
872 error_prepend(errp, "Failed to read export length: ");
873 goto fail;
874 }
875 be64_to_cpus(&info->size);
876
877 if (nbd_read(ioc, &info->flags, sizeof(info->flags), errp) < 0) {
878 error_prepend(errp, "Failed to read export flags: ");
879 goto fail;
880 }
881 be16_to_cpus(&info->flags);
882 } else if (magic == NBD_CLIENT_MAGIC) {
883 uint32_t oldflags;
884
885 if (name) {
886 error_setg(errp, "Server does not support export names");
887 goto fail;
888 }
889 if (tlscreds) {
890 error_setg(errp, "Server does not support STARTTLS");
891 goto fail;
892 }
893
894 if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {
895 error_prepend(errp, "Failed to read export length: ");
896 goto fail;
897 }
898 be64_to_cpus(&info->size);
899
900 if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) {
901 error_prepend(errp, "Failed to read export flags: ");
902 goto fail;
903 }
904 be32_to_cpus(&oldflags);
905 if (oldflags & ~0xffff) {
906 error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);
907 goto fail;
908 }
909 info->flags = oldflags;
910 } else {
911 error_setg(errp, "Bad magic received");
912 goto fail;
913 }
914
915 trace_nbd_receive_negotiate_size_flags(info->size, info->flags);
916 if (zeroes && nbd_drop(ioc, 124, errp) < 0) {
917 error_prepend(errp, "Failed to read reserved block: ");
918 goto fail;
919 }
920 rc = 0;
921
922 fail:
923 return rc;
924 }
925
926 #ifdef __linux__
927 int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info,
928 Error **errp)
929 {
930 unsigned long sector_size = MAX(BDRV_SECTOR_SIZE, info->min_block);
931 unsigned long sectors = info->size / sector_size;
932
933 /* FIXME: Once the kernel module is patched to honor block sizes,
934 * and to advertise that fact to user space, we should update the
935 * hand-off to the kernel to use any block sizes we learned. */
936 assert(!info->request_sizes);
937 if (info->size / sector_size != sectors) {
938 error_setg(errp, "Export size %" PRIu64 " too large for 32-bit kernel",
939 info->size);
940 return -E2BIG;
941 }
942
943 trace_nbd_init_set_socket();
944
945 if (ioctl(fd, NBD_SET_SOCK, (unsigned long) sioc->fd) < 0) {
946 int serrno = errno;
947 error_setg(errp, "Failed to set NBD socket");
948 return -serrno;
949 }
950
951 trace_nbd_init_set_block_size(sector_size);
952
953 if (ioctl(fd, NBD_SET_BLKSIZE, sector_size) < 0) {
954 int serrno = errno;
955 error_setg(errp, "Failed setting NBD block size");
956 return -serrno;
957 }
958
959 trace_nbd_init_set_size(sectors);
960 if (info->size % sector_size) {
961 trace_nbd_init_trailing_bytes(info->size % sector_size);
962 }
963
964 if (ioctl(fd, NBD_SET_SIZE_BLOCKS, sectors) < 0) {
965 int serrno = errno;
966 error_setg(errp, "Failed setting size (in blocks)");
967 return -serrno;
968 }
969
970 if (ioctl(fd, NBD_SET_FLAGS, (unsigned long) info->flags) < 0) {
971 if (errno == ENOTTY) {
972 int read_only = (info->flags & NBD_FLAG_READ_ONLY) != 0;
973 trace_nbd_init_set_readonly();
974
975 if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
976 int serrno = errno;
977 error_setg(errp, "Failed setting read-only attribute");
978 return -serrno;
979 }
980 } else {
981 int serrno = errno;
982 error_setg(errp, "Failed setting flags");
983 return -serrno;
984 }
985 }
986
987 trace_nbd_init_finish();
988
989 return 0;
990 }
991
992 int nbd_client(int fd)
993 {
994 int ret;
995 int serrno;
996
997 trace_nbd_client_loop();
998
999 ret = ioctl(fd, NBD_DO_IT);
1000 if (ret < 0 && errno == EPIPE) {
1001 /* NBD_DO_IT normally returns EPIPE when someone has disconnected
1002 * the socket via NBD_DISCONNECT. We do not want to return 1 in
1003 * that case.
1004 */
1005 ret = 0;
1006 }
1007 serrno = errno;
1008
1009 trace_nbd_client_loop_ret(ret, strerror(serrno));
1010
1011 trace_nbd_client_clear_queue();
1012 ioctl(fd, NBD_CLEAR_QUE);
1013
1014 trace_nbd_client_clear_socket();
1015 ioctl(fd, NBD_CLEAR_SOCK);
1016
1017 errno = serrno;
1018 return ret;
1019 }
1020
1021 int nbd_disconnect(int fd)
1022 {
1023 ioctl(fd, NBD_CLEAR_QUE);
1024 ioctl(fd, NBD_DISCONNECT);
1025 ioctl(fd, NBD_CLEAR_SOCK);
1026 return 0;
1027 }
1028
1029 #else
1030 int nbd_init(int fd, QIOChannelSocket *ioc, NBDExportInfo *info,
1031 Error **errp)
1032 {
1033 error_setg(errp, "nbd_init is only supported on Linux");
1034 return -ENOTSUP;
1035 }
1036
1037 int nbd_client(int fd)
1038 {
1039 return -ENOTSUP;
1040 }
1041 int nbd_disconnect(int fd)
1042 {
1043 return -ENOTSUP;
1044 }
1045 #endif
1046
1047 int nbd_send_request(QIOChannel *ioc, NBDRequest *request)
1048 {
1049 uint8_t buf[NBD_REQUEST_SIZE];
1050
1051 trace_nbd_send_request(request->from, request->len, request->handle,
1052 request->flags, request->type,
1053 nbd_cmd_lookup(request->type));
1054
1055 stl_be_p(buf, NBD_REQUEST_MAGIC);
1056 stw_be_p(buf + 4, request->flags);
1057 stw_be_p(buf + 6, request->type);
1058 stq_be_p(buf + 8, request->handle);
1059 stq_be_p(buf + 16, request->from);
1060 stl_be_p(buf + 24, request->len);
1061
1062 return nbd_write(ioc, buf, sizeof(buf), NULL);
1063 }
1064
1065 /* nbd_receive_simple_reply
1066 * Read simple reply except magic field (which should be already read).
1067 * Payload is not read (payload is possible for CMD_READ, but here we even
1068 * don't know whether it take place or not).
1069 */
1070 static int nbd_receive_simple_reply(QIOChannel *ioc, NBDSimpleReply *reply,
1071 Error **errp)
1072 {
1073 int ret;
1074
1075 assert(reply->magic == NBD_SIMPLE_REPLY_MAGIC);
1076
1077 ret = nbd_read(ioc, (uint8_t *)reply + sizeof(reply->magic),
1078 sizeof(*reply) - sizeof(reply->magic), errp);
1079 if (ret < 0) {
1080 return ret;
1081 }
1082
1083 be32_to_cpus(&reply->error);
1084 be64_to_cpus(&reply->handle);
1085
1086 return 0;
1087 }
1088
1089 /* nbd_receive_structured_reply_chunk
1090 * Read structured reply chunk except magic field (which should be already
1091 * read).
1092 * Payload is not read.
1093 */
1094 static int nbd_receive_structured_reply_chunk(QIOChannel *ioc,
1095 NBDStructuredReplyChunk *chunk,
1096 Error **errp)
1097 {
1098 int ret;
1099
1100 assert(chunk->magic == NBD_STRUCTURED_REPLY_MAGIC);
1101
1102 ret = nbd_read(ioc, (uint8_t *)chunk + sizeof(chunk->magic),
1103 sizeof(*chunk) - sizeof(chunk->magic), errp);
1104 if (ret < 0) {
1105 return ret;
1106 }
1107
1108 be16_to_cpus(&chunk->flags);
1109 be16_to_cpus(&chunk->type);
1110 be64_to_cpus(&chunk->handle);
1111 be32_to_cpus(&chunk->length);
1112
1113 return 0;
1114 }
1115
1116 /* nbd_receive_reply
1117 * Returns 1 on success
1118 * 0 on eof, when no data was read (errp is not set)
1119 * negative errno on failure (errp is set)
1120 */
1121 int nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp)
1122 {
1123 int ret;
1124 const char *type;
1125
1126 ret = nbd_read_eof(ioc, &reply->magic, sizeof(reply->magic), errp);
1127 if (ret <= 0) {
1128 return ret;
1129 }
1130
1131 be32_to_cpus(&reply->magic);
1132
1133 switch (reply->magic) {
1134 case NBD_SIMPLE_REPLY_MAGIC:
1135 ret = nbd_receive_simple_reply(ioc, &reply->simple, errp);
1136 if (ret < 0) {
1137 break;
1138 }
1139 trace_nbd_receive_simple_reply(reply->simple.error,
1140 nbd_err_lookup(reply->simple.error),
1141 reply->handle);
1142 break;
1143 case NBD_STRUCTURED_REPLY_MAGIC:
1144 ret = nbd_receive_structured_reply_chunk(ioc, &reply->structured, errp);
1145 if (ret < 0) {
1146 break;
1147 }
1148 type = nbd_reply_type_lookup(reply->structured.type);
1149 trace_nbd_receive_structured_reply_chunk(reply->structured.flags,
1150 reply->structured.type, type,
1151 reply->structured.handle,
1152 reply->structured.length);
1153 break;
1154 default:
1155 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", reply->magic);
1156 return -EINVAL;
1157 }
1158 if (ret < 0) {
1159 return ret;
1160 }
1161
1162 return 1;
1163 }
1164