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 24 #include "qemu-common.h" 25 #include "qemu/option.h" 26 #include "io/channel-socket.h" 27 #include "crypto/tlscreds.h" 28 29 /* Handshake phase structs - this struct is passed on the wire */ 30 31 struct nbd_option { 32 uint64_t magic; /* NBD_OPTS_MAGIC */ 33 uint32_t option; /* NBD_OPT_* */ 34 uint32_t length; 35 } QEMU_PACKED; 36 typedef struct nbd_option nbd_option; 37 38 struct nbd_opt_reply { 39 uint64_t magic; /* NBD_REP_MAGIC */ 40 uint32_t option; /* NBD_OPT_* */ 41 uint32_t type; /* NBD_REP_* */ 42 uint32_t length; 43 } QEMU_PACKED; 44 typedef struct nbd_opt_reply nbd_opt_reply; 45 46 /* Transmission phase structs 47 * 48 * Note: these are _NOT_ the same as the network representation of an NBD 49 * request and reply! 50 */ 51 struct NBDRequest { 52 uint64_t handle; 53 uint64_t from; 54 uint32_t len; 55 uint16_t flags; /* NBD_CMD_FLAG_* */ 56 uint16_t type; /* NBD_CMD_* */ 57 }; 58 typedef struct NBDRequest NBDRequest; 59 60 struct NBDReply { 61 uint64_t handle; 62 uint32_t error; 63 }; 64 typedef struct NBDReply NBDReply; 65 66 typedef struct NBDSimpleReply { 67 uint32_t magic; /* NBD_SIMPLE_REPLY_MAGIC */ 68 uint32_t error; 69 uint64_t handle; 70 } QEMU_PACKED NBDSimpleReply; 71 72 /* Transmission (export) flags: sent from server to client during handshake, 73 but describe what will happen during transmission */ 74 #define NBD_FLAG_HAS_FLAGS (1 << 0) /* Flags are there */ 75 #define NBD_FLAG_READ_ONLY (1 << 1) /* Device is read-only */ 76 #define NBD_FLAG_SEND_FLUSH (1 << 2) /* Send FLUSH */ 77 #define NBD_FLAG_SEND_FUA (1 << 3) /* Send FUA (Force Unit Access) */ 78 #define NBD_FLAG_ROTATIONAL (1 << 4) /* Use elevator algorithm - 79 rotational media */ 80 #define NBD_FLAG_SEND_TRIM (1 << 5) /* Send TRIM (discard) */ 81 #define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6) /* Send WRITE_ZEROES */ 82 83 /* New-style handshake (global) flags, sent from server to client, and 84 control what will happen during handshake phase. */ 85 #define NBD_FLAG_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */ 86 #define NBD_FLAG_NO_ZEROES (1 << 1) /* End handshake without zeroes. */ 87 88 /* New-style client flags, sent from client to server to control what happens 89 during handshake phase. */ 90 #define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */ 91 #define NBD_FLAG_C_NO_ZEROES (1 << 1) /* End handshake without zeroes. */ 92 93 /* Option requests. */ 94 #define NBD_OPT_EXPORT_NAME (1) 95 #define NBD_OPT_ABORT (2) 96 #define NBD_OPT_LIST (3) 97 /* #define NBD_OPT_PEEK_EXPORT (4) not in use */ 98 #define NBD_OPT_STARTTLS (5) 99 #define NBD_OPT_INFO (6) 100 #define NBD_OPT_GO (7) 101 #define NBD_OPT_STRUCTURED_REPLY (8) 102 103 /* Option reply types. */ 104 #define NBD_REP_ERR(value) ((UINT32_C(1) << 31) | (value)) 105 106 #define NBD_REP_ACK (1) /* Data sending finished. */ 107 #define NBD_REP_SERVER (2) /* Export description. */ 108 #define NBD_REP_INFO (3) /* NBD_OPT_INFO/GO. */ 109 110 #define NBD_REP_ERR_UNSUP NBD_REP_ERR(1) /* Unknown option */ 111 #define NBD_REP_ERR_POLICY NBD_REP_ERR(2) /* Server denied */ 112 #define NBD_REP_ERR_INVALID NBD_REP_ERR(3) /* Invalid length */ 113 #define NBD_REP_ERR_PLATFORM NBD_REP_ERR(4) /* Not compiled in */ 114 #define NBD_REP_ERR_TLS_REQD NBD_REP_ERR(5) /* TLS required */ 115 #define NBD_REP_ERR_UNKNOWN NBD_REP_ERR(6) /* Export unknown */ 116 #define NBD_REP_ERR_SHUTDOWN NBD_REP_ERR(7) /* Server shutting down */ 117 #define NBD_REP_ERR_BLOCK_SIZE_REQD NBD_REP_ERR(8) /* Need INFO_BLOCK_SIZE */ 118 119 /* Info types, used during NBD_REP_INFO */ 120 #define NBD_INFO_EXPORT 0 121 #define NBD_INFO_NAME 1 122 #define NBD_INFO_DESCRIPTION 2 123 #define NBD_INFO_BLOCK_SIZE 3 124 125 /* Request flags, sent from client to server during transmission phase */ 126 #define NBD_CMD_FLAG_FUA (1 << 0) /* 'force unit access' during write */ 127 #define NBD_CMD_FLAG_NO_HOLE (1 << 1) /* don't punch hole on zero run */ 128 129 /* Supported request types */ 130 enum { 131 NBD_CMD_READ = 0, 132 NBD_CMD_WRITE = 1, 133 NBD_CMD_DISC = 2, 134 NBD_CMD_FLUSH = 3, 135 NBD_CMD_TRIM = 4, 136 /* 5 reserved for failed experiment NBD_CMD_CACHE */ 137 NBD_CMD_WRITE_ZEROES = 6, 138 }; 139 140 #define NBD_DEFAULT_PORT 10809 141 142 /* Maximum size of a single READ/WRITE data buffer */ 143 #define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024) 144 145 /* Maximum size of an export name. The NBD spec requires 256 and 146 * suggests that servers support up to 4096, but we stick to only the 147 * required size so that we can stack-allocate the names, and because 148 * going larger would require an audit of more code to make sure we 149 * aren't overflowing some other buffer. */ 150 #define NBD_MAX_NAME_SIZE 256 151 152 /* Details collected by NBD_OPT_EXPORT_NAME and NBD_OPT_GO */ 153 struct NBDExportInfo { 154 /* Set by client before nbd_receive_negotiate() */ 155 bool request_sizes; 156 /* Set by server results during nbd_receive_negotiate() */ 157 uint64_t size; 158 uint16_t flags; 159 uint32_t min_block; 160 uint32_t opt_block; 161 uint32_t max_block; 162 }; 163 typedef struct NBDExportInfo NBDExportInfo; 164 165 int nbd_receive_negotiate(QIOChannel *ioc, const char *name, 166 QCryptoTLSCreds *tlscreds, const char *hostname, 167 QIOChannel **outioc, NBDExportInfo *info, 168 Error **errp); 169 int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info, 170 Error **errp); 171 int nbd_send_request(QIOChannel *ioc, NBDRequest *request); 172 int nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp); 173 int nbd_client(int fd); 174 int nbd_disconnect(int fd); 175 176 typedef struct NBDExport NBDExport; 177 typedef struct NBDClient NBDClient; 178 179 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size, 180 uint16_t nbdflags, void (*close)(NBDExport *), 181 bool writethrough, BlockBackend *on_eject_blk, 182 Error **errp); 183 void nbd_export_close(NBDExport *exp); 184 void nbd_export_get(NBDExport *exp); 185 void nbd_export_put(NBDExport *exp); 186 187 BlockBackend *nbd_export_get_blockdev(NBDExport *exp); 188 189 NBDExport *nbd_export_find(const char *name); 190 void nbd_export_set_name(NBDExport *exp, const char *name); 191 void nbd_export_set_description(NBDExport *exp, const char *description); 192 void nbd_export_close_all(void); 193 194 void nbd_client_new(NBDExport *exp, 195 QIOChannelSocket *sioc, 196 QCryptoTLSCreds *tlscreds, 197 const char *tlsaclname, 198 void (*close_fn)(NBDClient *, bool)); 199 void nbd_client_get(NBDClient *client); 200 void nbd_client_put(NBDClient *client); 201 202 void nbd_server_start(SocketAddress *addr, const char *tls_creds, 203 Error **errp); 204 205 #endif 206