nbd/client: Add x-dirty-bitmap to query bitmap from server
[qemu.git] / include / block / nbd.h
1 /*
2 * Copyright (C) 2016-2017 Red Hat, Inc.
3 * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
4 *
5 * Network Block Device
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 #ifndef NBD_H
21 #define NBD_H
22
23 #include "qapi/qapi-types-block.h"
24 #include "io/channel-socket.h"
25 #include "crypto/tlscreds.h"
26
27 /* Handshake phase structs - this struct is passed on the wire */
28
29 struct NBDOption {
30 uint64_t magic; /* NBD_OPTS_MAGIC */
31 uint32_t option; /* NBD_OPT_* */
32 uint32_t length;
33 } QEMU_PACKED;
34 typedef struct NBDOption NBDOption;
35
36 struct NBDOptionReply {
37 uint64_t magic; /* NBD_REP_MAGIC */
38 uint32_t option; /* NBD_OPT_* */
39 uint32_t type; /* NBD_REP_* */
40 uint32_t length;
41 } QEMU_PACKED;
42 typedef struct NBDOptionReply NBDOptionReply;
43
44 typedef struct NBDOptionReplyMetaContext {
45 NBDOptionReply h; /* h.type = NBD_REP_META_CONTEXT, h.length > 4 */
46 uint32_t context_id;
47 /* meta context name follows */
48 } QEMU_PACKED NBDOptionReplyMetaContext;
49
50 /* Transmission phase structs
51 *
52 * Note: these are _NOT_ the same as the network representation of an NBD
53 * request and reply!
54 */
55 struct NBDRequest {
56 uint64_t handle;
57 uint64_t from;
58 uint32_t len;
59 uint16_t flags; /* NBD_CMD_FLAG_* */
60 uint16_t type; /* NBD_CMD_* */
61 };
62 typedef struct NBDRequest NBDRequest;
63
64 typedef struct NBDSimpleReply {
65 uint32_t magic; /* NBD_SIMPLE_REPLY_MAGIC */
66 uint32_t error;
67 uint64_t handle;
68 } QEMU_PACKED NBDSimpleReply;
69
70 /* Header of all structured replies */
71 typedef struct NBDStructuredReplyChunk {
72 uint32_t magic; /* NBD_STRUCTURED_REPLY_MAGIC */
73 uint16_t flags; /* combination of NBD_REPLY_FLAG_* */
74 uint16_t type; /* NBD_REPLY_TYPE_* */
75 uint64_t handle; /* request handle */
76 uint32_t length; /* length of payload */
77 } QEMU_PACKED NBDStructuredReplyChunk;
78
79 typedef union NBDReply {
80 NBDSimpleReply simple;
81 NBDStructuredReplyChunk structured;
82 struct {
83 /* @magic and @handle fields have the same offset and size both in
84 * simple reply and structured reply chunk, so let them be accessible
85 * without ".simple." or ".structured." specification
86 */
87 uint32_t magic;
88 uint32_t _skip;
89 uint64_t handle;
90 } QEMU_PACKED;
91 } NBDReply;
92
93 /* Header of chunk for NBD_REPLY_TYPE_OFFSET_DATA */
94 typedef struct NBDStructuredReadData {
95 NBDStructuredReplyChunk h; /* h.length >= 9 */
96 uint64_t offset;
97 /* At least one byte of data payload follows, calculated from h.length */
98 } QEMU_PACKED NBDStructuredReadData;
99
100 /* Complete chunk for NBD_REPLY_TYPE_OFFSET_HOLE */
101 typedef struct NBDStructuredReadHole {
102 NBDStructuredReplyChunk h; /* h.length == 12 */
103 uint64_t offset;
104 uint32_t length;
105 } QEMU_PACKED NBDStructuredReadHole;
106
107 /* Header of all NBD_REPLY_TYPE_ERROR* errors */
108 typedef struct NBDStructuredError {
109 NBDStructuredReplyChunk h; /* h.length >= 6 */
110 uint32_t error;
111 uint16_t message_length;
112 } QEMU_PACKED NBDStructuredError;
113
114 /* Header of NBD_REPLY_TYPE_BLOCK_STATUS */
115 typedef struct NBDStructuredMeta {
116 NBDStructuredReplyChunk h; /* h.length >= 12 (at least one extent) */
117 uint32_t context_id;
118 /* extents follows */
119 } QEMU_PACKED NBDStructuredMeta;
120
121 /* Extent chunk for NBD_REPLY_TYPE_BLOCK_STATUS */
122 typedef struct NBDExtent {
123 uint32_t length;
124 uint32_t flags; /* NBD_STATE_* */
125 } QEMU_PACKED NBDExtent;
126
127 /* Transmission (export) flags: sent from server to client during handshake,
128 but describe what will happen during transmission */
129 #define NBD_FLAG_HAS_FLAGS (1 << 0) /* Flags are there */
130 #define NBD_FLAG_READ_ONLY (1 << 1) /* Device is read-only */
131 #define NBD_FLAG_SEND_FLUSH (1 << 2) /* Send FLUSH */
132 #define NBD_FLAG_SEND_FUA (1 << 3) /* Send FUA (Force Unit Access) */
133 #define NBD_FLAG_ROTATIONAL (1 << 4) /* Use elevator algorithm -
134 rotational media */
135 #define NBD_FLAG_SEND_TRIM (1 << 5) /* Send TRIM (discard) */
136 #define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6) /* Send WRITE_ZEROES */
137 #define NBD_FLAG_SEND_DF (1 << 7) /* Send DF (Do not Fragment) */
138 #define NBD_FLAG_SEND_CACHE (1 << 8) /* Send CACHE (prefetch) */
139
140 /* New-style handshake (global) flags, sent from server to client, and
141 control what will happen during handshake phase. */
142 #define NBD_FLAG_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */
143 #define NBD_FLAG_NO_ZEROES (1 << 1) /* End handshake without zeroes. */
144
145 /* New-style client flags, sent from client to server to control what happens
146 during handshake phase. */
147 #define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */
148 #define NBD_FLAG_C_NO_ZEROES (1 << 1) /* End handshake without zeroes. */
149
150 /* Option requests. */
151 #define NBD_OPT_EXPORT_NAME (1)
152 #define NBD_OPT_ABORT (2)
153 #define NBD_OPT_LIST (3)
154 /* #define NBD_OPT_PEEK_EXPORT (4) not in use */
155 #define NBD_OPT_STARTTLS (5)
156 #define NBD_OPT_INFO (6)
157 #define NBD_OPT_GO (7)
158 #define NBD_OPT_STRUCTURED_REPLY (8)
159 #define NBD_OPT_LIST_META_CONTEXT (9)
160 #define NBD_OPT_SET_META_CONTEXT (10)
161
162 /* Option reply types. */
163 #define NBD_REP_ERR(value) ((UINT32_C(1) << 31) | (value))
164
165 #define NBD_REP_ACK (1) /* Data sending finished. */
166 #define NBD_REP_SERVER (2) /* Export description. */
167 #define NBD_REP_INFO (3) /* NBD_OPT_INFO/GO. */
168 #define NBD_REP_META_CONTEXT (4) /* NBD_OPT_{LIST,SET}_META_CONTEXT */
169
170 #define NBD_REP_ERR_UNSUP NBD_REP_ERR(1) /* Unknown option */
171 #define NBD_REP_ERR_POLICY NBD_REP_ERR(2) /* Server denied */
172 #define NBD_REP_ERR_INVALID NBD_REP_ERR(3) /* Invalid length */
173 #define NBD_REP_ERR_PLATFORM NBD_REP_ERR(4) /* Not compiled in */
174 #define NBD_REP_ERR_TLS_REQD NBD_REP_ERR(5) /* TLS required */
175 #define NBD_REP_ERR_UNKNOWN NBD_REP_ERR(6) /* Export unknown */
176 #define NBD_REP_ERR_SHUTDOWN NBD_REP_ERR(7) /* Server shutting down */
177 #define NBD_REP_ERR_BLOCK_SIZE_REQD NBD_REP_ERR(8) /* Need INFO_BLOCK_SIZE */
178
179 /* Info types, used during NBD_REP_INFO */
180 #define NBD_INFO_EXPORT 0
181 #define NBD_INFO_NAME 1
182 #define NBD_INFO_DESCRIPTION 2
183 #define NBD_INFO_BLOCK_SIZE 3
184
185 /* Request flags, sent from client to server during transmission phase */
186 #define NBD_CMD_FLAG_FUA (1 << 0) /* 'force unit access' during write */
187 #define NBD_CMD_FLAG_NO_HOLE (1 << 1) /* don't punch hole on zero run */
188 #define NBD_CMD_FLAG_DF (1 << 2) /* don't fragment structured read */
189 #define NBD_CMD_FLAG_REQ_ONE (1 << 3) /* only one extent in BLOCK_STATUS
190 * reply chunk */
191
192 /* Supported request types */
193 enum {
194 NBD_CMD_READ = 0,
195 NBD_CMD_WRITE = 1,
196 NBD_CMD_DISC = 2,
197 NBD_CMD_FLUSH = 3,
198 NBD_CMD_TRIM = 4,
199 NBD_CMD_CACHE = 5,
200 NBD_CMD_WRITE_ZEROES = 6,
201 NBD_CMD_BLOCK_STATUS = 7,
202 };
203
204 #define NBD_DEFAULT_PORT 10809
205
206 /* Maximum size of a single READ/WRITE data buffer */
207 #define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024)
208
209 /* Maximum size of an export name. The NBD spec requires 256 and
210 * suggests that servers support up to 4096, but we stick to only the
211 * required size so that we can stack-allocate the names, and because
212 * going larger would require an audit of more code to make sure we
213 * aren't overflowing some other buffer. */
214 #define NBD_MAX_NAME_SIZE 256
215
216 /* Two types of reply structures */
217 #define NBD_SIMPLE_REPLY_MAGIC 0x67446698
218 #define NBD_STRUCTURED_REPLY_MAGIC 0x668e33ef
219
220 /* Structured reply flags */
221 #define NBD_REPLY_FLAG_DONE (1 << 0) /* This reply-chunk is last */
222
223 /* Structured reply types */
224 #define NBD_REPLY_ERR(value) ((1 << 15) | (value))
225
226 #define NBD_REPLY_TYPE_NONE 0
227 #define NBD_REPLY_TYPE_OFFSET_DATA 1
228 #define NBD_REPLY_TYPE_OFFSET_HOLE 2
229 #define NBD_REPLY_TYPE_BLOCK_STATUS 5
230 #define NBD_REPLY_TYPE_ERROR NBD_REPLY_ERR(1)
231 #define NBD_REPLY_TYPE_ERROR_OFFSET NBD_REPLY_ERR(2)
232
233 /* Extent flags for base:allocation in NBD_REPLY_TYPE_BLOCK_STATUS */
234 #define NBD_STATE_HOLE (1 << 0)
235 #define NBD_STATE_ZERO (1 << 1)
236
237 /* Extent flags for qemu:dirty-bitmap in NBD_REPLY_TYPE_BLOCK_STATUS */
238 #define NBD_STATE_DIRTY (1 << 0)
239
240 static inline bool nbd_reply_type_is_error(int type)
241 {
242 return type & (1 << 15);
243 }
244
245 /* NBD errors are based on errno numbers, so there is a 1:1 mapping,
246 * but only a limited set of errno values is specified in the protocol.
247 * Everything else is squashed to EINVAL.
248 */
249 #define NBD_SUCCESS 0
250 #define NBD_EPERM 1
251 #define NBD_EIO 5
252 #define NBD_ENOMEM 12
253 #define NBD_EINVAL 22
254 #define NBD_ENOSPC 28
255 #define NBD_EOVERFLOW 75
256 #define NBD_ESHUTDOWN 108
257
258 /* Details collected by NBD_OPT_EXPORT_NAME and NBD_OPT_GO */
259 struct NBDExportInfo {
260 /* Set by client before nbd_receive_negotiate() */
261 bool request_sizes;
262 char *x_dirty_bitmap;
263
264 /* In-out fields, set by client before nbd_receive_negotiate() and
265 * updated by server results during nbd_receive_negotiate() */
266 bool structured_reply;
267 bool base_allocation; /* base:allocation context for NBD_CMD_BLOCK_STATUS */
268
269 /* Set by server results during nbd_receive_negotiate() */
270 uint64_t size;
271 uint16_t flags;
272 uint32_t min_block;
273 uint32_t opt_block;
274 uint32_t max_block;
275
276 uint32_t meta_base_allocation_id;
277 };
278 typedef struct NBDExportInfo NBDExportInfo;
279
280 int nbd_receive_negotiate(QIOChannel *ioc, const char *name,
281 QCryptoTLSCreds *tlscreds, const char *hostname,
282 QIOChannel **outioc, NBDExportInfo *info,
283 Error **errp);
284 int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info,
285 Error **errp);
286 int nbd_send_request(QIOChannel *ioc, NBDRequest *request);
287 int nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp);
288 int nbd_client(int fd);
289 int nbd_disconnect(int fd);
290 int nbd_errno_to_system_errno(int err);
291
292 typedef struct NBDExport NBDExport;
293 typedef struct NBDClient NBDClient;
294
295 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
296 uint16_t nbdflags, void (*close)(NBDExport *),
297 bool writethrough, BlockBackend *on_eject_blk,
298 Error **errp);
299 void nbd_export_close(NBDExport *exp);
300 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp);
301 void nbd_export_get(NBDExport *exp);
302 void nbd_export_put(NBDExport *exp);
303
304 BlockBackend *nbd_export_get_blockdev(NBDExport *exp);
305
306 NBDExport *nbd_export_find(const char *name);
307 void nbd_export_set_name(NBDExport *exp, const char *name);
308 void nbd_export_set_description(NBDExport *exp, const char *description);
309 void nbd_export_close_all(void);
310
311 void nbd_client_new(NBDExport *exp,
312 QIOChannelSocket *sioc,
313 QCryptoTLSCreds *tlscreds,
314 const char *tlsaclname,
315 void (*close_fn)(NBDClient *, bool));
316 void nbd_client_get(NBDClient *client);
317 void nbd_client_put(NBDClient *client);
318
319 void nbd_server_start(SocketAddress *addr, const char *tls_creds,
320 Error **errp);
321
322 void nbd_export_bitmap(NBDExport *exp, const char *bitmap,
323 const char *bitmap_export_name, Error **errp);
324
325 /* nbd_read
326 * Reads @size bytes from @ioc. Returns 0 on success.
327 */
328 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
329 Error **errp)
330 {
331 return qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
332 }
333
334 static inline bool nbd_reply_is_simple(NBDReply *reply)
335 {
336 return reply->magic == NBD_SIMPLE_REPLY_MAGIC;
337 }
338
339 static inline bool nbd_reply_is_structured(NBDReply *reply)
340 {
341 return reply->magic == NBD_STRUCTURED_REPLY_MAGIC;
342 }
343
344 const char *nbd_reply_type_lookup(uint16_t type);
345
346 #endif