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