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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/qmp/qerror.h" | |
17 | #include "sysemu/sysemu.h" | |
18 | #include "qmp-commands.h" | |
19 | #include "block/nbd.h" | |
20 | #include "io/channel-socket.h" | |
21 | ||
22 | typedef struct NBDServerData { | |
23 | QIOChannelSocket *listen_ioc; | |
24 | int watch; | |
25 | QCryptoTLSCreds *tlscreds; | |
26 | } NBDServerData; | |
27 | ||
28 | static NBDServerData *nbd_server; | |
29 | ||
30 | ||
31 | static gboolean nbd_accept(QIOChannel *ioc, GIOCondition condition, | |
32 | gpointer opaque) | |
33 | { | |
34 | QIOChannelSocket *cioc; | |
35 | ||
36 | if (!nbd_server) { | |
37 | return FALSE; | |
38 | } | |
39 | ||
40 | cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc), | |
41 | NULL); | |
42 | if (!cioc) { | |
43 | return TRUE; | |
44 | } | |
45 | ||
46 | qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server"); | |
47 | nbd_client_new(NULL, cioc, | |
48 | nbd_server->tlscreds, NULL, | |
49 | nbd_client_put); | |
50 | object_unref(OBJECT(cioc)); | |
51 | return TRUE; | |
52 | } | |
53 | ||
54 | ||
55 | static void nbd_server_free(NBDServerData *server) | |
56 | { | |
57 | if (!server) { | |
58 | return; | |
59 | } | |
60 | ||
61 | if (server->watch != -1) { | |
62 | g_source_remove(server->watch); | |
63 | } | |
64 | object_unref(OBJECT(server->listen_ioc)); | |
65 | if (server->tlscreds) { | |
66 | object_unref(OBJECT(server->tlscreds)); | |
67 | } | |
68 | ||
69 | g_free(server); | |
70 | } | |
71 | ||
72 | static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp) | |
73 | { | |
74 | Object *obj; | |
75 | QCryptoTLSCreds *creds; | |
76 | ||
77 | obj = object_resolve_path_component( | |
78 | object_get_objects_root(), id); | |
79 | if (!obj) { | |
80 | error_setg(errp, "No TLS credentials with id '%s'", | |
81 | id); | |
82 | return NULL; | |
83 | } | |
84 | creds = (QCryptoTLSCreds *) | |
85 | object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS); | |
86 | if (!creds) { | |
87 | error_setg(errp, "Object with id '%s' is not TLS credentials", | |
88 | id); | |
89 | return NULL; | |
90 | } | |
91 | ||
92 | if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) { | |
93 | error_setg(errp, | |
94 | "Expecting TLS credentials with a server endpoint"); | |
95 | return NULL; | |
96 | } | |
97 | object_ref(obj); | |
98 | return creds; | |
99 | } | |
100 | ||
101 | ||
102 | void qmp_nbd_server_start(SocketAddress *addr, | |
103 | bool has_tls_creds, const char *tls_creds, | |
104 | Error **errp) | |
105 | { | |
106 | if (nbd_server) { | |
107 | error_setg(errp, "NBD server already running"); | |
108 | return; | |
109 | } | |
110 | ||
111 | nbd_server = g_new0(NBDServerData, 1); | |
112 | nbd_server->watch = -1; | |
113 | nbd_server->listen_ioc = qio_channel_socket_new(); | |
114 | qio_channel_set_name(QIO_CHANNEL(nbd_server->listen_ioc), | |
115 | "nbd-listener"); | |
116 | if (qio_channel_socket_listen_sync( | |
117 | nbd_server->listen_ioc, addr, errp) < 0) { | |
118 | goto error; | |
119 | } | |
120 | ||
121 | if (has_tls_creds) { | |
122 | nbd_server->tlscreds = nbd_get_tls_creds(tls_creds, errp); | |
123 | if (!nbd_server->tlscreds) { | |
124 | goto error; | |
125 | } | |
126 | ||
127 | /* TODO SOCKET_ADDRESS_KIND_FD where fd has AF_INET or AF_INET6 */ | |
128 | if (addr->type != SOCKET_ADDRESS_KIND_INET) { | |
129 | error_setg(errp, "TLS is only supported with IPv4/IPv6"); | |
130 | goto error; | |
131 | } | |
132 | } | |
133 | ||
134 | nbd_server->watch = qio_channel_add_watch( | |
135 | QIO_CHANNEL(nbd_server->listen_ioc), | |
136 | G_IO_IN, | |
137 | nbd_accept, | |
138 | NULL, | |
139 | NULL); | |
140 | ||
141 | return; | |
142 | ||
143 | error: | |
144 | nbd_server_free(nbd_server); | |
145 | nbd_server = NULL; | |
146 | } | |
147 | ||
148 | void qmp_nbd_server_add(const char *device, bool has_writable, bool writable, | |
149 | Error **errp) | |
150 | { | |
151 | BlockDriverState *bs = NULL; | |
152 | BlockBackend *on_eject_blk; | |
153 | NBDExport *exp; | |
154 | ||
155 | if (!nbd_server) { | |
156 | error_setg(errp, "NBD server not running"); | |
157 | return; | |
158 | } | |
159 | ||
160 | if (nbd_export_find(device)) { | |
161 | error_setg(errp, "NBD server already exporting device '%s'", device); | |
162 | return; | |
163 | } | |
164 | ||
165 | on_eject_blk = blk_by_name(device); | |
166 | ||
167 | bs = bdrv_lookup_bs(device, device, errp); | |
168 | if (!bs) { | |
169 | return; | |
170 | } | |
171 | ||
172 | if (!has_writable) { | |
173 | writable = false; | |
174 | } | |
175 | if (bdrv_is_read_only(bs)) { | |
176 | writable = false; | |
177 | } | |
178 | ||
179 | exp = nbd_export_new(bs, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY, | |
180 | NULL, false, on_eject_blk, errp); | |
181 | if (!exp) { | |
182 | return; | |
183 | } | |
184 | ||
185 | nbd_export_set_name(exp, device); | |
186 | ||
187 | /* The list of named exports has a strong reference to this export now and | |
188 | * our only way of accessing it is through nbd_export_find(), so we can drop | |
189 | * the strong reference that is @exp. */ | |
190 | nbd_export_put(exp); | |
191 | } | |
192 | ||
193 | void qmp_nbd_server_stop(Error **errp) | |
194 | { | |
195 | nbd_export_close_all(); | |
196 | ||
197 | nbd_server_free(nbd_server); | |
198 | nbd_server = NULL; | |
199 | } |