xref: /qemu/block/nbd.c (revision 58369e22) 
1 /*
2  * QEMU Block driver for  NBD
3  *
4  * Copyright (C) 2008 Bull S.A.S.
5  *     Author: Laurent Vivier <Laurent.Vivier@bull.net>
6  *
7  * Some parts:
8  *    Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws>
9  *
10  * Permission is hereby granted, free of charge, to any person obtaining a copy
11  * of this software and associated documentation files (the "Software"), to deal
12  * in the Software without restriction, including without limitation the rights
13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14  * copies of the Software, and to permit persons to whom the Software is
15  * furnished to do so, subject to the following conditions:
16  *
17  * The above copyright notice and this permission notice shall be included in
18  * all copies or substantial portions of the Software.
19  *
20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26  * THE SOFTWARE.
27  */
28 
29 #include "qemu/osdep.h"
30 #include "block/nbd-client.h"
31 #include "qapi/error.h"
32 #include "qemu/uri.h"
33 #include "block/block_int.h"
34 #include "qemu/module.h"
35 #include "qapi/qmp/qdict.h"
36 #include "qapi/qmp/qjson.h"
37 #include "qapi/qmp/qint.h"
38 #include "qapi/qmp/qstring.h"
39 #include "qemu/cutils.h"
40 
41 #define EN_OPTSTR ":exportname="
42 
43 typedef struct BDRVNBDState {
44     NbdClientSession client;
45 } BDRVNBDState;
46 
47 static int nbd_parse_uri(const char *filename, QDict *options)
48 {
49     URI *uri;
50     const char *p;
51     QueryParams *qp = NULL;
52     int ret = 0;
53     bool is_unix;
54 
55     uri = uri_parse(filename);
56     if (!uri) {
57         return -EINVAL;
58     }
59 
60     /* transport */
61     if (!strcmp(uri->scheme, "nbd")) {
62         is_unix = false;
63     } else if (!strcmp(uri->scheme, "nbd+tcp")) {
64         is_unix = false;
65     } else if (!strcmp(uri->scheme, "nbd+unix")) {
66         is_unix = true;
67     } else {
68         ret = -EINVAL;
69         goto out;
70     }
71 
72     p = uri->path ? uri->path : "/";
73     p += strspn(p, "/");
74     if (p[0]) {
75         qdict_put(options, "export", qstring_from_str(p));
76     }
77 
78     qp = query_params_parse(uri->query);
79     if (qp->n > 1 || (is_unix && !qp->n) || (!is_unix && qp->n)) {
80         ret = -EINVAL;
81         goto out;
82     }
83 
84     if (is_unix) {
85         /* nbd+unix:///export?socket=path */
86         if (uri->server || uri->port || strcmp(qp->p[0].name, "socket")) {
87             ret = -EINVAL;
88             goto out;
89         }
90         qdict_put(options, "path", qstring_from_str(qp->p[0].value));
91     } else {
92         QString *host;
93         /* nbd[+tcp]://host[:port]/export */
94         if (!uri->server) {
95             ret = -EINVAL;
96             goto out;
97         }
98 
99         /* strip braces from literal IPv6 address */
100         if (uri->server[0] == '[') {
101             host = qstring_from_substr(uri->server, 1,
102                                        strlen(uri->server) - 2);
103         } else {
104             host = qstring_from_str(uri->server);
105         }
106 
107         qdict_put(options, "host", host);
108         if (uri->port) {
109             char* port_str = g_strdup_printf("%d", uri->port);
110             qdict_put(options, "port", qstring_from_str(port_str));
111             g_free(port_str);
112         }
113     }
114 
115 out:
116     if (qp) {
117         query_params_free(qp);
118     }
119     uri_free(uri);
120     return ret;
121 }
122 
123 static void nbd_parse_filename(const char *filename, QDict *options,
124                                Error **errp)
125 {
126     char *file;
127     char *export_name;
128     const char *host_spec;
129     const char *unixpath;
130 
131     if (qdict_haskey(options, "host")
132         || qdict_haskey(options, "port")
133         || qdict_haskey(options, "path"))
134     {
135         error_setg(errp, "host/port/path and a file name may not be specified "
136                          "at the same time");
137         return;
138     }
139 
140     if (strstr(filename, "://")) {
141         int ret = nbd_parse_uri(filename, options);
142         if (ret < 0) {
143             error_setg(errp, "No valid URL specified");
144         }
145         return;
146     }
147 
148     file = g_strdup(filename);
149 
150     export_name = strstr(file, EN_OPTSTR);
151     if (export_name) {
152         if (export_name[strlen(EN_OPTSTR)] == 0) {
153             goto out;
154         }
155         export_name[0] = 0; /* truncate 'file' */
156         export_name += strlen(EN_OPTSTR);
157 
158         qdict_put(options, "export", qstring_from_str(export_name));
159     }
160 
161     /* extract the host_spec - fail if it's not nbd:... */
162     if (!strstart(file, "nbd:", &host_spec)) {
163         error_setg(errp, "File name string for NBD must start with 'nbd:'");
164         goto out;
165     }
166 
167     if (!*host_spec) {
168         goto out;
169     }
170 
171     /* are we a UNIX or TCP socket? */
172     if (strstart(host_spec, "unix:", &unixpath)) {
173         qdict_put(options, "path", qstring_from_str(unixpath));
174     } else {
175         InetSocketAddress *addr = NULL;
176 
177         addr = inet_parse(host_spec, errp);
178         if (!addr) {
179             goto out;
180         }
181 
182         qdict_put(options, "host", qstring_from_str(addr->host));
183         qdict_put(options, "port", qstring_from_str(addr->port));
184         qapi_free_InetSocketAddress(addr);
185     }
186 
187 out:
188     g_free(file);
189 }
190 
191 static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options, char **export,
192                                  Error **errp)
193 {
194     SocketAddress *saddr;
195 
196     if (qdict_haskey(options, "path") == qdict_haskey(options, "host")) {
197         if (qdict_haskey(options, "path")) {
198             error_setg(errp, "path and host may not be used at the same time.");
199         } else {
200             error_setg(errp, "one of path and host must be specified.");
201         }
202         return NULL;
203     }
204 
205     saddr = g_new0(SocketAddress, 1);
206 
207     if (qdict_haskey(options, "path")) {
208         UnixSocketAddress *q_unix;
209         saddr->type = SOCKET_ADDRESS_KIND_UNIX;
210         q_unix = saddr->u.q_unix.data = g_new0(UnixSocketAddress, 1);
211         q_unix->path = g_strdup(qdict_get_str(options, "path"));
212         qdict_del(options, "path");
213     } else {
214         InetSocketAddress *inet;
215         saddr->type = SOCKET_ADDRESS_KIND_INET;
216         inet = saddr->u.inet.data = g_new0(InetSocketAddress, 1);
217         inet->host = g_strdup(qdict_get_str(options, "host"));
218         if (!qdict_get_try_str(options, "port")) {
219             inet->port = g_strdup_printf("%d", NBD_DEFAULT_PORT);
220         } else {
221             inet->port = g_strdup(qdict_get_str(options, "port"));
222         }
223         qdict_del(options, "host");
224         qdict_del(options, "port");
225     }
226 
227     s->client.is_unix = saddr->type == SOCKET_ADDRESS_KIND_UNIX;
228 
229     *export = g_strdup(qdict_get_try_str(options, "export"));
230     if (*export) {
231         qdict_del(options, "export");
232     }
233 
234     return saddr;
235 }
236 
237 NbdClientSession *nbd_get_client_session(BlockDriverState *bs)
238 {
239     BDRVNBDState *s = bs->opaque;
240     return &s->client;
241 }
242 
243 static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
244                                                   Error **errp)
245 {
246     QIOChannelSocket *sioc;
247     Error *local_err = NULL;
248 
249     sioc = qio_channel_socket_new();
250 
251     qio_channel_socket_connect_sync(sioc,
252                                     saddr,
253                                     &local_err);
254     if (local_err) {
255         error_propagate(errp, local_err);
256         return NULL;
257     }
258 
259     qio_channel_set_delay(QIO_CHANNEL(sioc), false);
260 
261     return sioc;
262 }
263 
264 
265 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
266 {
267     Object *obj;
268     QCryptoTLSCreds *creds;
269 
270     obj = object_resolve_path_component(
271         object_get_objects_root(), id);
272     if (!obj) {
273         error_setg(errp, "No TLS credentials with id '%s'",
274                    id);
275         return NULL;
276     }
277     creds = (QCryptoTLSCreds *)
278         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
279     if (!creds) {
280         error_setg(errp, "Object with id '%s' is not TLS credentials",
281                    id);
282         return NULL;
283     }
284 
285     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
286         error_setg(errp,
287                    "Expecting TLS credentials with a client endpoint");
288         return NULL;
289     }
290     object_ref(obj);
291     return creds;
292 }
293 
294 
295 static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
296                     Error **errp)
297 {
298     BDRVNBDState *s = bs->opaque;
299     char *export = NULL;
300     QIOChannelSocket *sioc = NULL;
301     SocketAddress *saddr;
302     const char *tlscredsid;
303     QCryptoTLSCreds *tlscreds = NULL;
304     const char *hostname = NULL;
305     int ret = -EINVAL;
306 
307     /* Pop the config into our state object. Exit if invalid. */
308     saddr = nbd_config(s, options, &export, errp);
309     if (!saddr) {
310         goto error;
311     }
312 
313     tlscredsid = g_strdup(qdict_get_try_str(options, "tls-creds"));
314     if (tlscredsid) {
315         qdict_del(options, "tls-creds");
316         tlscreds = nbd_get_tls_creds(tlscredsid, errp);
317         if (!tlscreds) {
318             goto error;
319         }
320 
321         if (saddr->type != SOCKET_ADDRESS_KIND_INET) {
322             error_setg(errp, "TLS only supported over IP sockets");
323             goto error;
324         }
325         hostname = saddr->u.inet.data->host;
326     }
327 
328     /* establish TCP connection, return error if it fails
329      * TODO: Configurable retry-until-timeout behaviour.
330      */
331     sioc = nbd_establish_connection(saddr, errp);
332     if (!sioc) {
333         ret = -ECONNREFUSED;
334         goto error;
335     }
336 
337     /* NBD handshake */
338     ret = nbd_client_init(bs, sioc, export,
339                           tlscreds, hostname, errp);
340  error:
341     if (sioc) {
342         object_unref(OBJECT(sioc));
343     }
344     if (tlscreds) {
345         object_unref(OBJECT(tlscreds));
346     }
347     qapi_free_SocketAddress(saddr);
348     g_free(export);
349     return ret;
350 }
351 
352 static int nbd_co_readv(BlockDriverState *bs, int64_t sector_num,
353                         int nb_sectors, QEMUIOVector *qiov)
354 {
355     return nbd_client_co_readv(bs, sector_num, nb_sectors, qiov);
356 }
357 
358 static int nbd_co_flush(BlockDriverState *bs)
359 {
360     return nbd_client_co_flush(bs);
361 }
362 
363 static void nbd_refresh_limits(BlockDriverState *bs, Error **errp)
364 {
365     bs->bl.max_discard = UINT32_MAX >> BDRV_SECTOR_BITS;
366     bs->bl.max_transfer_length = UINT32_MAX >> BDRV_SECTOR_BITS;
367 }
368 
369 static int nbd_co_discard(BlockDriverState *bs, int64_t sector_num,
370                           int nb_sectors)
371 {
372     return nbd_client_co_discard(bs, sector_num, nb_sectors);
373 }
374 
375 static void nbd_close(BlockDriverState *bs)
376 {
377     nbd_client_close(bs);
378 }
379 
380 static int64_t nbd_getlength(BlockDriverState *bs)
381 {
382     BDRVNBDState *s = bs->opaque;
383 
384     return s->client.size;
385 }
386 
387 static void nbd_detach_aio_context(BlockDriverState *bs)
388 {
389     nbd_client_detach_aio_context(bs);
390 }
391 
392 static void nbd_attach_aio_context(BlockDriverState *bs,
393                                    AioContext *new_context)
394 {
395     nbd_client_attach_aio_context(bs, new_context);
396 }
397 
398 static void nbd_refresh_filename(BlockDriverState *bs, QDict *options)
399 {
400     QDict *opts = qdict_new();
401     const char *path   = qdict_get_try_str(options, "path");
402     const char *host   = qdict_get_try_str(options, "host");
403     const char *port   = qdict_get_try_str(options, "port");
404     const char *export = qdict_get_try_str(options, "export");
405     const char *tlscreds = qdict_get_try_str(options, "tls-creds");
406 
407     qdict_put_obj(opts, "driver", QOBJECT(qstring_from_str("nbd")));
408 
409     if (path && export) {
410         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
411                  "nbd+unix:///%s?socket=%s", export, path);
412     } else if (path && !export) {
413         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
414                  "nbd+unix://?socket=%s", path);
415     } else if (!path && export && port) {
416         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
417                  "nbd://%s:%s/%s", host, port, export);
418     } else if (!path && export && !port) {
419         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
420                  "nbd://%s/%s", host, export);
421     } else if (!path && !export && port) {
422         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
423                  "nbd://%s:%s", host, port);
424     } else if (!path && !export && !port) {
425         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
426                  "nbd://%s", host);
427     }
428 
429     if (path) {
430         qdict_put_obj(opts, "path", QOBJECT(qstring_from_str(path)));
431     } else if (port) {
432         qdict_put_obj(opts, "host", QOBJECT(qstring_from_str(host)));
433         qdict_put_obj(opts, "port", QOBJECT(qstring_from_str(port)));
434     } else {
435         qdict_put_obj(opts, "host", QOBJECT(qstring_from_str(host)));
436     }
437     if (export) {
438         qdict_put_obj(opts, "export", QOBJECT(qstring_from_str(export)));
439     }
440     if (tlscreds) {
441         qdict_put_obj(opts, "tls-creds", QOBJECT(qstring_from_str(tlscreds)));
442     }
443 
444     bs->full_open_options = opts;
445 }
446 
447 static BlockDriver bdrv_nbd = {
448     .format_name                = "nbd",
449     .protocol_name              = "nbd",
450     .instance_size              = sizeof(BDRVNBDState),
451     .bdrv_parse_filename        = nbd_parse_filename,
452     .bdrv_file_open             = nbd_open,
453     .bdrv_co_readv              = nbd_co_readv,
454     .bdrv_co_writev_flags       = nbd_client_co_writev,
455     .bdrv_close                 = nbd_close,
456     .bdrv_co_flush_to_os        = nbd_co_flush,
457     .bdrv_co_discard            = nbd_co_discard,
458     .bdrv_refresh_limits        = nbd_refresh_limits,
459     .bdrv_getlength             = nbd_getlength,
460     .bdrv_detach_aio_context    = nbd_detach_aio_context,
461     .bdrv_attach_aio_context    = nbd_attach_aio_context,
462     .bdrv_refresh_filename      = nbd_refresh_filename,
463 };
464 
465 static BlockDriver bdrv_nbd_tcp = {
466     .format_name                = "nbd",
467     .protocol_name              = "nbd+tcp",
468     .instance_size              = sizeof(BDRVNBDState),
469     .bdrv_parse_filename        = nbd_parse_filename,
470     .bdrv_file_open             = nbd_open,
471     .bdrv_co_readv              = nbd_co_readv,
472     .bdrv_co_writev_flags       = nbd_client_co_writev,
473     .bdrv_close                 = nbd_close,
474     .bdrv_co_flush_to_os        = nbd_co_flush,
475     .bdrv_co_discard            = nbd_co_discard,
476     .bdrv_refresh_limits        = nbd_refresh_limits,
477     .bdrv_getlength             = nbd_getlength,
478     .bdrv_detach_aio_context    = nbd_detach_aio_context,
479     .bdrv_attach_aio_context    = nbd_attach_aio_context,
480     .bdrv_refresh_filename      = nbd_refresh_filename,
481 };
482 
483 static BlockDriver bdrv_nbd_unix = {
484     .format_name                = "nbd",
485     .protocol_name              = "nbd+unix",
486     .instance_size              = sizeof(BDRVNBDState),
487     .bdrv_parse_filename        = nbd_parse_filename,
488     .bdrv_file_open             = nbd_open,
489     .bdrv_co_readv              = nbd_co_readv,
490     .bdrv_co_writev_flags       = nbd_client_co_writev,
491     .bdrv_close                 = nbd_close,
492     .bdrv_co_flush_to_os        = nbd_co_flush,
493     .bdrv_co_discard            = nbd_co_discard,
494     .bdrv_refresh_limits        = nbd_refresh_limits,
495     .bdrv_getlength             = nbd_getlength,
496     .bdrv_detach_aio_context    = nbd_detach_aio_context,
497     .bdrv_attach_aio_context    = nbd_attach_aio_context,
498     .bdrv_refresh_filename      = nbd_refresh_filename,
499 };
500 
501 static void bdrv_nbd_init(void)
502 {
503     bdrv_register(&bdrv_nbd);
504     bdrv_register(&bdrv_nbd_tcp);
505     bdrv_register(&bdrv_nbd_unix);
506 }
507 
508 block_init(bdrv_nbd_init);
509