1/*
2 * Copyright (C) 2016-2019 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#include "qapi/error.h"
27
28/* Handshake phase structs - this struct is passed on the wire */
29
30struct NBDOption {
31 uint64_t magic; /* NBD_OPTS_MAGIC */
32 uint32_t option; /* NBD_OPT_* */
33 uint32_t length;
34} QEMU_PACKED;
35typedef struct NBDOption NBDOption;
36
37struct NBDOptionReply {
38 uint64_t magic; /* NBD_REP_MAGIC */
39 uint32_t option; /* NBD_OPT_* */
40 uint32_t type; /* NBD_REP_* */
41 uint32_t length;
42} QEMU_PACKED;
43typedef struct NBDOptionReply NBDOptionReply;
44
45typedef struct NBDOptionReplyMetaContext {
46 NBDOptionReply h; /* h.type = NBD_REP_META_CONTEXT, h.length > 4 */
47 uint32_t context_id;
48 /* meta context name follows */
49} QEMU_PACKED NBDOptionReplyMetaContext;
50
51/* Transmission phase structs
52 *
53 * Note: these are _NOT_ the same as the network representation of an NBD
54 * request and reply!
55 */
56struct NBDRequest {
57 uint64_t handle;
58 uint64_t from;
59 uint32_t len;
60 uint16_t flags; /* NBD_CMD_FLAG_* */
61 uint16_t type; /* NBD_CMD_* */
62};
63typedef struct NBDRequest NBDRequest;
64
65typedef struct NBDSimpleReply {
66 uint32_t magic; /* NBD_SIMPLE_REPLY_MAGIC */
67 uint32_t error;
68 uint64_t handle;
69} QEMU_PACKED NBDSimpleReply;
70
71/* Header of all structured replies */
72typedef struct NBDStructuredReplyChunk {
73 uint32_t magic; /* NBD_STRUCTURED_REPLY_MAGIC */
74 uint16_t flags; /* combination of NBD_REPLY_FLAG_* */
75 uint16_t type; /* NBD_REPLY_TYPE_* */
76 uint64_t handle; /* request handle */
77 uint32_t length; /* length of payload */
78} QEMU_PACKED NBDStructuredReplyChunk;
79
80typedef union NBDReply {
81 NBDSimpleReply simple;
82 NBDStructuredReplyChunk structured;
83 struct {
84 /* @magic and @handle fields have the same offset and size both in
85 * simple reply and structured reply chunk, so let them be accessible
86 * without ".simple." or ".structured." specification
87 */
88 uint32_t magic;
89 uint32_t _skip;
90 uint64_t handle;
91 } QEMU_PACKED;
92} NBDReply;
93
94/* Header of chunk for NBD_REPLY_TYPE_OFFSET_DATA */
95typedef struct NBDStructuredReadData {
96 NBDStructuredReplyChunk h; /* h.length >= 9 */
97 uint64_t offset;
98 /* At least one byte of data payload follows, calculated from h.length */
99} QEMU_PACKED NBDStructuredReadData;
100
101/* Complete chunk for NBD_REPLY_TYPE_OFFSET_HOLE */
102typedef struct NBDStructuredReadHole {
103 NBDStructuredReplyChunk h; /* h.length == 12 */
104 uint64_t offset;
105 uint32_t length;
106} QEMU_PACKED NBDStructuredReadHole;
107
108/* Header of all NBD_REPLY_TYPE_ERROR* errors */
109typedef struct NBDStructuredError {
110 NBDStructuredReplyChunk h; /* h.length >= 6 */
111 uint32_t error;
112 uint16_t message_length;
113} QEMU_PACKED NBDStructuredError;
114
115/* Header of NBD_REPLY_TYPE_BLOCK_STATUS */
116typedef struct NBDStructuredMeta {
117 NBDStructuredReplyChunk h; /* h.length >= 12 (at least one extent) */
118 uint32_t context_id;
119 /* extents follows */
120} QEMU_PACKED NBDStructuredMeta;
121
122/* Extent chunk for NBD_REPLY_TYPE_BLOCK_STATUS */
123typedef struct NBDExtent {
124 uint32_t length;
125 uint32_t flags; /* NBD_STATE_* */
126} QEMU_PACKED NBDExtent;
127
128/* Transmission (export) flags: sent from server to client during handshake,
129 but describe what will happen during transmission */
130enum {
131 NBD_FLAG_HAS_FLAGS_BIT = 0, /* Flags are there */
132 NBD_FLAG_READ_ONLY_BIT = 1, /* Device is read-only */
133 NBD_FLAG_SEND_FLUSH_BIT = 2, /* Send FLUSH */
134 NBD_FLAG_SEND_FUA_BIT = 3, /* Send FUA (Force Unit Access) */
135 NBD_FLAG_ROTATIONAL_BIT = 4, /* Use elevator algorithm -
136 rotational media */
137 NBD_FLAG_SEND_TRIM_BIT = 5, /* Send TRIM (discard) */
138 NBD_FLAG_SEND_WRITE_ZEROES_BIT = 6, /* Send WRITE_ZEROES */
139 NBD_FLAG_SEND_DF_BIT = 7, /* Send DF (Do not Fragment) */
140 NBD_FLAG_CAN_MULTI_CONN_BIT = 8, /* Multi-client cache consistent */
141 NBD_FLAG_SEND_RESIZE_BIT = 9, /* Send resize */
142 NBD_FLAG_SEND_CACHE_BIT = 10, /* Send CACHE (prefetch) */
143};
144
145#define NBD_FLAG_HAS_FLAGS (1 << NBD_FLAG_HAS_FLAGS_BIT)
146#define NBD_FLAG_READ_ONLY (1 << NBD_FLAG_READ_ONLY_BIT)
147#define NBD_FLAG_SEND_FLUSH (1 << NBD_FLAG_SEND_FLUSH_BIT)
148#define NBD_FLAG_SEND_FUA (1 << NBD_FLAG_SEND_FUA_BIT)
149#define NBD_FLAG_ROTATIONAL (1 << NBD_FLAG_ROTATIONAL_BIT)
150#define NBD_FLAG_SEND_TRIM (1 << NBD_FLAG_SEND_TRIM_BIT)
151#define NBD_FLAG_SEND_WRITE_ZEROES (1 << NBD_FLAG_SEND_WRITE_ZEROES_BIT)
152#define NBD_FLAG_SEND_DF (1 << NBD_FLAG_SEND_DF_BIT)
153#define NBD_FLAG_CAN_MULTI_CONN (1 << NBD_FLAG_CAN_MULTI_CONN_BIT)
154#define NBD_FLAG_SEND_RESIZE (1 << NBD_FLAG_SEND_RESIZE_BIT)
155#define NBD_FLAG_SEND_CACHE (1 << NBD_FLAG_SEND_CACHE_BIT)
156
157/* New-style handshake (global) flags, sent from server to client, and
158 control what will happen during handshake phase. */
159#define NBD_FLAG_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */
160#define NBD_FLAG_NO_ZEROES (1 << 1) /* End handshake without zeroes. */
161
162/* New-style client flags, sent from client to server to control what happens
163 during handshake phase. */
164#define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */
165#define NBD_FLAG_C_NO_ZEROES (1 << 1) /* End handshake without zeroes. */
166
167/* Option requests. */
168#define NBD_OPT_EXPORT_NAME (1)
169#define NBD_OPT_ABORT (2)
170#define NBD_OPT_LIST (3)
171/* #define NBD_OPT_PEEK_EXPORT (4) not in use */
172#define NBD_OPT_STARTTLS (5)
173#define NBD_OPT_INFO (6)
174#define NBD_OPT_GO (7)
175#define NBD_OPT_STRUCTURED_REPLY (8)
176#define NBD_OPT_LIST_META_CONTEXT (9)
177#define NBD_OPT_SET_META_CONTEXT (10)
178
179/* Option reply types. */
180#define NBD_REP_ERR(value) ((UINT32_C(1) << 31) | (value))
181
182#define NBD_REP_ACK (1) /* Data sending finished. */
183#define NBD_REP_SERVER (2) /* Export description. */
184#define NBD_REP_INFO (3) /* NBD_OPT_INFO/GO. */
185#define NBD_REP_META_CONTEXT (4) /* NBD_OPT_{LIST,SET}_META_CONTEXT */
186
187#define NBD_REP_ERR_UNSUP NBD_REP_ERR(1) /* Unknown option */
188#define NBD_REP_ERR_POLICY NBD_REP_ERR(2) /* Server denied */
189#define NBD_REP_ERR_INVALID NBD_REP_ERR(3) /* Invalid length */
190#define NBD_REP_ERR_PLATFORM NBD_REP_ERR(4) /* Not compiled in */
191#define NBD_REP_ERR_TLS_REQD NBD_REP_ERR(5) /* TLS required */
192#define NBD_REP_ERR_UNKNOWN NBD_REP_ERR(6) /* Export unknown */
193#define NBD_REP_ERR_SHUTDOWN NBD_REP_ERR(7) /* Server shutting down */
194#define NBD_REP_ERR_BLOCK_SIZE_REQD NBD_REP_ERR(8) /* Need INFO_BLOCK_SIZE */
195
196/* Info types, used during NBD_REP_INFO */
197#define NBD_INFO_EXPORT 0
198#define NBD_INFO_NAME 1
199#define NBD_INFO_DESCRIPTION 2
200#define NBD_INFO_BLOCK_SIZE 3
201
202/* Request flags, sent from client to server during transmission phase */
203#define NBD_CMD_FLAG_FUA (1 << 0) /* 'force unit access' during write */
204#define NBD_CMD_FLAG_NO_HOLE (1 << 1) /* don't punch hole on zero run */
205#define NBD_CMD_FLAG_DF (1 << 2) /* don't fragment structured read */
206#define NBD_CMD_FLAG_REQ_ONE (1 << 3) /* only one extent in BLOCK_STATUS
207 * reply chunk */
208
209/* Supported request types */
210enum {
211 NBD_CMD_READ = 0,
212 NBD_CMD_WRITE = 1,
213 NBD_CMD_DISC = 2,
214 NBD_CMD_FLUSH = 3,
215 NBD_CMD_TRIM = 4,
216 NBD_CMD_CACHE = 5,
217 NBD_CMD_WRITE_ZEROES = 6,
218 NBD_CMD_BLOCK_STATUS = 7,
219};
220
221#define NBD_DEFAULT_PORT 10809
222
223/* Maximum size of a single READ/WRITE data buffer */
224#define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024)
225
226/* Maximum size of an export name. The NBD spec requires 256 and
227 * suggests that servers support up to 4096, but we stick to only the
228 * required size so that we can stack-allocate the names, and because
229 * going larger would require an audit of more code to make sure we
230 * aren't overflowing some other buffer. */
231#define NBD_MAX_NAME_SIZE 256
232
233/* Two types of reply structures */
234#define NBD_SIMPLE_REPLY_MAGIC 0x67446698
235#define NBD_STRUCTURED_REPLY_MAGIC 0x668e33ef
236
237/* Structured reply flags */
238#define NBD_REPLY_FLAG_DONE (1 << 0) /* This reply-chunk is last */
239
240/* Structured reply types */
241#define NBD_REPLY_ERR(value) ((1 << 15) | (value))
242
243#define NBD_REPLY_TYPE_NONE 0
244#define NBD_REPLY_TYPE_OFFSET_DATA 1
245#define NBD_REPLY_TYPE_OFFSET_HOLE 2
246#define NBD_REPLY_TYPE_BLOCK_STATUS 5
247#define NBD_REPLY_TYPE_ERROR NBD_REPLY_ERR(1)
248#define NBD_REPLY_TYPE_ERROR_OFFSET NBD_REPLY_ERR(2)
249
250/* Extent flags for base:allocation in NBD_REPLY_TYPE_BLOCK_STATUS */
251#define NBD_STATE_HOLE (1 << 0)
252#define NBD_STATE_ZERO (1 << 1)
253
254/* Extent flags for qemu:dirty-bitmap in NBD_REPLY_TYPE_BLOCK_STATUS */
255#define NBD_STATE_DIRTY (1 << 0)
256
257static inline bool nbd_reply_type_is_error(int type)
258{
259 return type & (1 << 15);
260}
261
262/* NBD errors are based on errno numbers, so there is a 1:1 mapping,
263 * but only a limited set of errno values is specified in the protocol.
264 * Everything else is squashed to EINVAL.
265 */
266#define NBD_SUCCESS 0
267#define NBD_EPERM 1
268#define NBD_EIO 5
269#define NBD_ENOMEM 12
270#define NBD_EINVAL 22
271#define NBD_ENOSPC 28
272#define NBD_EOVERFLOW 75
273#define NBD_ESHUTDOWN 108
274
275/* Details collected by NBD_OPT_EXPORT_NAME and NBD_OPT_GO */
276struct NBDExportInfo {
277 /* Set by client before nbd_receive_negotiate() */
278 bool request_sizes;
279 char *x_dirty_bitmap;
280
281 /* Set by client before nbd_receive_negotiate(), or by server results
282 * during nbd_receive_export_list() */
283 char *name; /* must be non-NULL */
284
285 /* In-out fields, set by client before nbd_receive_negotiate() and
286 * updated by server results during nbd_receive_negotiate() */
287 bool structured_reply;
288 bool base_allocation; /* base:allocation context for NBD_CMD_BLOCK_STATUS */
289
290 /* Set by server results during nbd_receive_negotiate() and
291 * nbd_receive_export_list() */
292 uint64_t size;
293 uint16_t flags;
294 uint32_t min_block;
295 uint32_t opt_block;
296 uint32_t max_block;
297
298 uint32_t context_id;
299
300 /* Set by server results during nbd_receive_export_list() */
301 char *description;
302 int n_contexts;
303 char **contexts;
304};
305typedef struct NBDExportInfo NBDExportInfo;
306
307int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
308 QCryptoTLSCreds *tlscreds,
309 const char *hostname, QIOChannel **outioc,
310 NBDExportInfo *info, Error **errp);
311void nbd_free_export_list(NBDExportInfo *info, int count);
312int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
313 const char *hostname, NBDExportInfo **info,
314 Error **errp);
315int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info,
316 Error **errp);
317int nbd_send_request(QIOChannel *ioc, NBDRequest *request);
318int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc,
319 NBDReply *reply, Error **errp);
320int nbd_client(int fd);
321int nbd_disconnect(int fd);
322int nbd_errno_to_system_errno(int err);
323
324typedef struct NBDExport NBDExport;
325typedef struct NBDClient NBDClient;
326
327NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
328 uint64_t size, const char *name, const char *desc,
329 const char *bitmap, uint16_t nbdflags,
330 void (*close)(NBDExport *), bool writethrough,
331 BlockBackend *on_eject_blk, Error **errp);
332void nbd_export_close(NBDExport *exp);
333void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp);
334void nbd_export_get(NBDExport *exp);
335void nbd_export_put(NBDExport *exp);
336
337BlockBackend *nbd_export_get_blockdev(NBDExport *exp);
338
339NBDExport *nbd_export_find(const char *name);
340void nbd_export_close_all(void);
341
342void nbd_client_new(QIOChannelSocket *sioc,
343 QCryptoTLSCreds *tlscreds,
344 const char *tlsauthz,
345 void (*close_fn)(NBDClient *, bool));
346void nbd_client_get(NBDClient *client);
347void nbd_client_put(NBDClient *client);
348
349void nbd_server_start(SocketAddress *addr, const char *tls_creds,
350 const char *tls_authz, Error **errp);
351
352/* nbd_read
353 * Reads @size bytes from @ioc. Returns 0 on success.
354 */
355static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
356 const char *desc, Error **errp)
357{
358 int ret = qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
359
360 if (ret < 0) {
361 if (desc) {
362 error_prepend(errp, "Failed to read %s: ", desc);
363 }
364 return -1;
365 }
366
367 return 0;
368}
369
370#define DEF_NBD_READ_N(bits) \
371static inline int nbd_read##bits(QIOChannel *ioc, \
372 uint##bits##_t *val, \
373 const char *desc, Error **errp) \
374{ \
375 if (nbd_read(ioc, val, sizeof(*val), desc, errp) < 0) { \
376 return -1; \
377 } \
378 *val = be##bits##_to_cpu(*val); \
379 return 0; \
380}
381
382DEF_NBD_READ_N(16) /* Defines nbd_read16(). */
383DEF_NBD_READ_N(32) /* Defines nbd_read32(). */
384DEF_NBD_READ_N(64) /* Defines nbd_read64(). */
385
386#undef DEF_NBD_READ_N
387
388static inline bool nbd_reply_is_simple(NBDReply *reply)
389{
390 return reply->magic == NBD_SIMPLE_REPLY_MAGIC;
391}
392
393static inline bool nbd_reply_is_structured(NBDReply *reply)
394{
395 return reply->magic == NBD_STRUCTURED_REPLY_MAGIC;
396}
397
398const char *nbd_reply_type_lookup(uint16_t type);
399const char *nbd_opt_lookup(uint32_t opt);
400const char *nbd_rep_lookup(uint32_t rep);
401const char *nbd_info_lookup(uint16_t info);
402const char *nbd_cmd_lookup(uint16_t info);
403const char *nbd_err_lookup(int err);
404
405#endif
406