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1 /*
2 * Serving QEMU block devices via NBD
3 *
4 * Copyright (c) 2012 Red Hat, Inc.
5 *
6 * Author: Paolo Bonzini <pbonzini@redhat.com>
7 *
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.
10 */
11
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.h"
18 #include "sysemu/sysemu.h"
19 #include "block/nbd.h"
20 #include "io/channel-socket.h"
21 #include "io/net-listener.h"
22
23 typedef struct NBDServerData {
24 QIONetListener *listener;
25 QCryptoTLSCreds *tlscreds;
26 char *tlsauthz;
27 } NBDServerData;
28
29 static NBDServerData *nbd_server;
30
31 static void nbd_blockdev_client_closed(NBDClient *client, bool ignored)
32 {
33 nbd_client_put(client);
34 }
35
36 static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
37 gpointer opaque)
38 {
39 qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server");
40 nbd_client_new(cioc, nbd_server->tlscreds, nbd_server->tlsauthz,
41 nbd_blockdev_client_closed);
42 }
43
44
45 static void nbd_server_free(NBDServerData *server)
46 {
47 if (!server) {
48 return;
49 }
50
51 qio_net_listener_disconnect(server->listener);
52 object_unref(OBJECT(server->listener));
53 if (server->tlscreds) {
54 object_unref(OBJECT(server->tlscreds));
55 }
56 g_free(server->tlsauthz);
57
58 g_free(server);
59 }
60
61 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
62 {
63 Object *obj;
64 QCryptoTLSCreds *creds;
65
66 obj = object_resolve_path_component(
67 object_get_objects_root(), id);
68 if (!obj) {
69 error_setg(errp, "No TLS credentials with id '%s'",
70 id);
71 return NULL;
72 }
73 creds = (QCryptoTLSCreds *)
74 object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
75 if (!creds) {
76 error_setg(errp, "Object with id '%s' is not TLS credentials",
77 id);
78 return NULL;
79 }
80
81 if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
82 error_setg(errp,
83 "Expecting TLS credentials with a server endpoint");
84 return NULL;
85 }
86 object_ref(obj);
87 return creds;
88 }
89
90
91 void nbd_server_start(SocketAddress *addr, const char *tls_creds,
92 const char *tls_authz, Error **errp)
93 {
94 if (nbd_server) {
95 error_setg(errp, "NBD server already running");
96 return;
97 }
98
99 nbd_server = g_new0(NBDServerData, 1);
100 nbd_server->listener = qio_net_listener_new();
101
102 qio_net_listener_set_name(nbd_server->listener,
103 "nbd-listener");
104
105 if (qio_net_listener_open_sync(nbd_server->listener, addr, errp) < 0) {
106 goto error;
107 }
108
109 if (tls_creds) {
110 nbd_server->tlscreds = nbd_get_tls_creds(tls_creds, errp);
111 if (!nbd_server->tlscreds) {
112 goto error;
113 }
114
115 /* TODO SOCKET_ADDRESS_TYPE_FD where fd has AF_INET or AF_INET6 */
116 if (addr->type != SOCKET_ADDRESS_TYPE_INET) {
117 error_setg(errp, "TLS is only supported with IPv4/IPv6");
118 goto error;
119 }
120 }
121
122 nbd_server->tlsauthz = g_strdup(tls_authz);
123
124 qio_net_listener_set_client_func(nbd_server->listener,
125 nbd_accept,
126 NULL,
127 NULL);
128
129 return;
130
131 error:
132 nbd_server_free(nbd_server);
133 nbd_server = NULL;
134 }
135
136 void qmp_nbd_server_start(SocketAddressLegacy *addr,
137 bool has_tls_creds, const char *tls_creds,
138 bool has_tls_authz, const char *tls_authz,
139 Error **errp)
140 {
141 SocketAddress *addr_flat = socket_address_flatten(addr);
142
143 nbd_server_start(addr_flat, tls_creds, tls_authz, errp);
144 qapi_free_SocketAddress(addr_flat);
145 }
146
147 void qmp_nbd_server_add(const char *device, bool has_name, const char *name,
148 bool has_writable, bool writable,
149 bool has_bitmap, const char *bitmap, Error **errp)
150 {
151 BlockDriverState *bs = NULL;
152 BlockBackend *on_eject_blk;
153 NBDExport *exp;
154 int64_t len;
155
156 if (!nbd_server) {
157 error_setg(errp, "NBD server not running");
158 return;
159 }
160
161 if (!has_name) {
162 name = device;
163 }
164
165 if (nbd_export_find(name)) {
166 error_setg(errp, "NBD server already has export named '%s'", name);
167 return;
168 }
169
170 on_eject_blk = blk_by_name(device);
171
172 bs = bdrv_lookup_bs(device, device, errp);
173 if (!bs) {
174 return;
175 }
176
177 len = bdrv_getlength(bs);
178 if (len < 0) {
179 error_setg_errno(errp, -len,
180 "Failed to determine the NBD export's length");
181 return;
182 }
183
184 if (!has_writable) {
185 writable = false;
186 }
187 if (bdrv_is_read_only(bs)) {
188 writable = false;
189 }
190
191 exp = nbd_export_new(bs, 0, len, name, NULL, bitmap,
192 writable ? 0 : NBD_FLAG_READ_ONLY,
193 NULL, false, on_eject_blk, errp);
194 if (!exp) {
195 return;
196 }
197
198 /* The list of named exports has a strong reference to this export now and
199 * our only way of accessing it is through nbd_export_find(), so we can drop
200 * the strong reference that is @exp. */
201 nbd_export_put(exp);
202 }
203
204 void qmp_nbd_server_remove(const char *name,
205 bool has_mode, NbdServerRemoveMode mode,
206 Error **errp)
207 {
208 NBDExport *exp;
209
210 if (!nbd_server) {
211 error_setg(errp, "NBD server not running");
212 return;
213 }
214
215 exp = nbd_export_find(name);
216 if (exp == NULL) {
217 error_setg(errp, "Export '%s' is not found", name);
218 return;
219 }
220
221 if (!has_mode) {
222 mode = NBD_SERVER_REMOVE_MODE_SAFE;
223 }
224
225 nbd_export_remove(exp, mode, errp);
226 }
227
228 void qmp_nbd_server_stop(Error **errp)
229 {
230 if (!nbd_server) {
231 error_setg(errp, "NBD server not running");
232 return;
233 }
234
235 nbd_export_close_all();
236
237 nbd_server_free(nbd_server);
238 nbd_server = NULL;
239 }