nbd: Avoid magic number for NBD max name size
[qemu.git] / include / block / nbd.h
1 /*
2 * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
3 *
4 * Network Block Device
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; under version 2 of the License.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, see <http://www.gnu.org/licenses/>.
17 */
18
19 #ifndef NBD_H
20 #define NBD_H
21
22
23 #include "qemu-common.h"
24 #include "qemu/option.h"
25 #include "io/channel-socket.h"
26 #include "crypto/tlscreds.h"
27
28 /* Note: these are _NOT_ the same as the network representation of an NBD
29 * request and reply!
30 */
31 struct nbd_request {
32 uint64_t handle;
33 uint64_t from;
34 uint32_t len;
35 uint32_t type;
36 };
37
38 struct nbd_reply {
39 uint64_t handle;
40 uint32_t error;
41 };
42
43 #define NBD_FLAG_HAS_FLAGS (1 << 0) /* Flags are there */
44 #define NBD_FLAG_READ_ONLY (1 << 1) /* Device is read-only */
45 #define NBD_FLAG_SEND_FLUSH (1 << 2) /* Send FLUSH */
46 #define NBD_FLAG_SEND_FUA (1 << 3) /* Send FUA (Force Unit Access) */
47 #define NBD_FLAG_ROTATIONAL (1 << 4) /* Use elevator algorithm - rotational media */
48 #define NBD_FLAG_SEND_TRIM (1 << 5) /* Send TRIM (discard) */
49
50 /* New-style global flags. */
51 #define NBD_FLAG_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */
52
53 /* New-style client flags. */
54 #define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */
55
56 /* Reply types. */
57 #define NBD_REP_ACK (1) /* Data sending finished. */
58 #define NBD_REP_SERVER (2) /* Export description. */
59 #define NBD_REP_ERR_UNSUP ((UINT32_C(1) << 31) | 1) /* Unknown option. */
60 #define NBD_REP_ERR_POLICY ((UINT32_C(1) << 31) | 2) /* Server denied */
61 #define NBD_REP_ERR_INVALID ((UINT32_C(1) << 31) | 3) /* Invalid length. */
62 #define NBD_REP_ERR_TLS_REQD ((UINT32_C(1) << 31) | 5) /* TLS required */
63
64
65 #define NBD_CMD_MASK_COMMAND 0x0000ffff
66 #define NBD_CMD_FLAG_FUA (1 << 16)
67
68 enum {
69 NBD_CMD_READ = 0,
70 NBD_CMD_WRITE = 1,
71 NBD_CMD_DISC = 2,
72 NBD_CMD_FLUSH = 3,
73 NBD_CMD_TRIM = 4
74 };
75
76 #define NBD_DEFAULT_PORT 10809
77
78 /* Maximum size of a single READ/WRITE data buffer */
79 #define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024)
80 /* Maximum size of an export name. The NBD spec requires 256 and
81 * suggests that servers support up to 4096, but we stick to only the
82 * required size so that we can stack-allocate the names, and because
83 * going larger would require an audit of more code to make sure we
84 * aren't overflowing some other buffer. */
85 #define NBD_MAX_NAME_SIZE 256
86
87 ssize_t nbd_wr_syncv(QIOChannel *ioc,
88 struct iovec *iov,
89 size_t niov,
90 size_t offset,
91 size_t length,
92 bool do_read);
93 int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint32_t *flags,
94 QCryptoTLSCreds *tlscreds, const char *hostname,
95 QIOChannel **outioc,
96 off_t *size, Error **errp);
97 int nbd_init(int fd, QIOChannelSocket *sioc, uint32_t flags, off_t size);
98 ssize_t nbd_send_request(QIOChannel *ioc, struct nbd_request *request);
99 ssize_t nbd_receive_reply(QIOChannel *ioc, struct nbd_reply *reply);
100 int nbd_client(int fd);
101 int nbd_disconnect(int fd);
102
103 typedef struct NBDExport NBDExport;
104 typedef struct NBDClient NBDClient;
105
106 NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
107 uint32_t nbdflags, void (*close)(NBDExport *),
108 Error **errp);
109 void nbd_export_close(NBDExport *exp);
110 void nbd_export_get(NBDExport *exp);
111 void nbd_export_put(NBDExport *exp);
112
113 BlockBackend *nbd_export_get_blockdev(NBDExport *exp);
114
115 NBDExport *nbd_export_find(const char *name);
116 void nbd_export_set_name(NBDExport *exp, const char *name);
117 void nbd_export_close_all(void);
118
119 void nbd_client_new(NBDExport *exp,
120 QIOChannelSocket *sioc,
121 QCryptoTLSCreds *tlscreds,
122 const char *tlsaclname,
123 void (*close)(NBDClient *));
124 void nbd_client_get(NBDClient *client);
125 void nbd_client_put(NBDClient *client);
126
127 #endif