2 * Serving QEMU block devices via NBD
4 * Copyright (c) 2012 Red Hat, Inc.
6 * Author: Paolo Bonzini <pbonzini@redhat.com>
8 * This work is licensed under the terms of the GNU GPL, version 2 or
9 * later. See the COPYING file in the top-level directory.
12 #include "qemu/osdep.h"
13 #include "sysemu/blockdev.h"
14 #include "sysemu/block-backend.h"
15 #include "hw/block/block.h"
16 #include "qapi/error.h"
17 #include "qapi/qapi-commands-block-export.h"
18 #include "block/nbd.h"
19 #include "io/channel-socket.h"
20 #include "io/net-listener.h"
22 typedef struct NBDServerData
{
23 QIONetListener
*listener
;
24 QCryptoTLSCreds
*tlscreds
;
26 uint32_t max_connections
;
30 static NBDServerData
*nbd_server
;
32 static void nbd_update_server_watch(NBDServerData
*s
);
34 static void nbd_blockdev_client_closed(NBDClient
*client
, bool ignored
)
36 nbd_client_put(client
);
37 assert(nbd_server
->connections
> 0);
38 nbd_server
->connections
--;
39 nbd_update_server_watch(nbd_server
);
42 static void nbd_accept(QIONetListener
*listener
, QIOChannelSocket
*cioc
,
45 nbd_server
->connections
++;
46 nbd_update_server_watch(nbd_server
);
48 qio_channel_set_name(QIO_CHANNEL(cioc
), "nbd-server");
49 nbd_client_new(cioc
, nbd_server
->tlscreds
, nbd_server
->tlsauthz
,
50 nbd_blockdev_client_closed
);
53 static void nbd_update_server_watch(NBDServerData
*s
)
55 if (!s
->max_connections
|| s
->connections
< s
->max_connections
) {
56 qio_net_listener_set_client_func(s
->listener
, nbd_accept
, NULL
, NULL
);
58 qio_net_listener_set_client_func(s
->listener
, NULL
, NULL
, NULL
);
62 static void nbd_server_free(NBDServerData
*server
)
68 qio_net_listener_disconnect(server
->listener
);
69 object_unref(OBJECT(server
->listener
));
70 if (server
->tlscreds
) {
71 object_unref(OBJECT(server
->tlscreds
));
73 g_free(server
->tlsauthz
);
78 static QCryptoTLSCreds
*nbd_get_tls_creds(const char *id
, Error
**errp
)
81 QCryptoTLSCreds
*creds
;
83 obj
= object_resolve_path_component(
84 object_get_objects_root(), id
);
86 error_setg(errp
, "No TLS credentials with id '%s'",
90 creds
= (QCryptoTLSCreds
*)
91 object_dynamic_cast(obj
, TYPE_QCRYPTO_TLS_CREDS
);
93 error_setg(errp
, "Object with id '%s' is not TLS credentials",
98 if (creds
->endpoint
!= QCRYPTO_TLS_CREDS_ENDPOINT_SERVER
) {
100 "Expecting TLS credentials with a server endpoint");
108 void nbd_server_start(SocketAddress
*addr
, const char *tls_creds
,
109 const char *tls_authz
, uint32_t max_connections
,
113 error_setg(errp
, "NBD server already running");
117 nbd_server
= g_new0(NBDServerData
, 1);
118 nbd_server
->max_connections
= max_connections
;
119 nbd_server
->listener
= qio_net_listener_new();
121 qio_net_listener_set_name(nbd_server
->listener
,
124 if (qio_net_listener_open_sync(nbd_server
->listener
, addr
, 1, errp
) < 0) {
129 nbd_server
->tlscreds
= nbd_get_tls_creds(tls_creds
, errp
);
130 if (!nbd_server
->tlscreds
) {
134 /* TODO SOCKET_ADDRESS_TYPE_FD where fd has AF_INET or AF_INET6 */
135 if (addr
->type
!= SOCKET_ADDRESS_TYPE_INET
) {
136 error_setg(errp
, "TLS is only supported with IPv4/IPv6");
141 nbd_server
->tlsauthz
= g_strdup(tls_authz
);
143 nbd_update_server_watch(nbd_server
);
148 nbd_server_free(nbd_server
);
152 void nbd_server_start_options(NbdServerOptions
*arg
, Error
**errp
)
154 nbd_server_start(arg
->addr
, arg
->tls_creds
, arg
->tls_authz
,
155 arg
->max_connections
, errp
);
158 void qmp_nbd_server_start(SocketAddressLegacy
*addr
,
159 bool has_tls_creds
, const char *tls_creds
,
160 bool has_tls_authz
, const char *tls_authz
,
161 bool has_max_connections
, uint32_t max_connections
,
164 SocketAddress
*addr_flat
= socket_address_flatten(addr
);
166 nbd_server_start(addr_flat
, tls_creds
, tls_authz
, max_connections
, errp
);
167 qapi_free_SocketAddress(addr_flat
);
170 BlockExport
*nbd_export_create(BlockExportOptions
*exp_args
, Error
**errp
)
172 BlockExportOptionsNbd
*arg
= &exp_args
->u
.nbd
;
173 BlockDriverState
*bs
= NULL
;
174 NBDExport
*exp
= NULL
;
175 AioContext
*aio_context
;
177 assert(exp_args
->type
== BLOCK_EXPORT_TYPE_NBD
);
180 error_setg(errp
, "NBD server not running");
184 if (!arg
->has_name
) {
185 arg
->name
= arg
->device
;
188 if (strlen(arg
->name
) > NBD_MAX_STRING_SIZE
) {
189 error_setg(errp
, "export name '%s' too long", arg
->name
);
193 if (arg
->description
&& strlen(arg
->description
) > NBD_MAX_STRING_SIZE
) {
194 error_setg(errp
, "description '%s' too long", arg
->description
);
198 if (nbd_export_find(arg
->name
)) {
199 error_setg(errp
, "NBD server already has export named '%s'", arg
->name
);
203 bs
= bdrv_lookup_bs(arg
->device
, arg
->device
, errp
);
208 aio_context
= bdrv_get_aio_context(bs
);
209 aio_context_acquire(aio_context
);
211 if (!arg
->has_writable
) {
212 arg
->writable
= false;
214 if (bdrv_is_read_only(bs
) && arg
->writable
) {
215 error_setg(errp
, "Cannot export read-only node as writable");
219 if (!exp_args
->has_writethrough
) {
220 exp_args
->writethrough
= false;
223 exp
= nbd_export_new(bs
, arg
->name
, arg
->description
, arg
->bitmap
,
224 !arg
->writable
, !arg
->writable
,
225 exp_args
->writethrough
, errp
);
230 /* The list of named exports has a strong reference to this export now and
231 * our only way of accessing it is through nbd_export_find(), so we can drop
232 * the strong reference that is @exp. */
236 aio_context_release(aio_context
);
237 /* TODO Remove the cast: nbd_export_new() will return a BlockExport. */
238 return (BlockExport
*) exp
;
241 void qmp_nbd_server_add(BlockExportOptionsNbd
*arg
, Error
**errp
)
244 BlockDriverState
*bs
;
245 BlockBackend
*on_eject_blk
;
246 BlockExportOptions export_opts
;
248 bs
= bdrv_lookup_bs(arg
->device
, arg
->device
, errp
);
253 export_opts
= (BlockExportOptions
) {
254 .type
= BLOCK_EXPORT_TYPE_NBD
,
259 * nbd-server-add doesn't complain when a read-only device should be
260 * exported as writable, but simply downgrades it. This is an error with
263 if (bdrv_is_read_only(bs
)) {
264 export_opts
.u
.nbd
.has_writable
= true;
265 export_opts
.u
.nbd
.writable
= false;
268 export
= blk_exp_add(&export_opts
, errp
);
274 * nbd-server-add removes the export when the named BlockBackend used for
277 on_eject_blk
= blk_by_name(arg
->device
);
279 nbd_export_set_on_eject_blk(export
, on_eject_blk
);
283 void qmp_nbd_server_remove(const char *name
,
284 bool has_mode
, NbdServerRemoveMode mode
,
288 AioContext
*aio_context
;
291 error_setg(errp
, "NBD server not running");
295 exp
= nbd_export_find(name
);
297 error_setg(errp
, "Export '%s' is not found", name
);
302 mode
= NBD_SERVER_REMOVE_MODE_SAFE
;
305 aio_context
= nbd_export_aio_context(exp
);
306 aio_context_acquire(aio_context
);
307 nbd_export_remove(exp
, mode
, errp
);
308 aio_context_release(aio_context
);
311 void qmp_nbd_server_stop(Error
**errp
)
314 error_setg(errp
, "NBD server not running");
318 nbd_export_close_all();
320 nbd_server_free(nbd_server
);