| 1 | /* |
| 2 | * Copyright Red Hat |
| 3 | * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws> |
| 4 | * |
| 5 | * Network Block Device Client Side |
| 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 | #include "qemu/osdep.h" |
| 21 | #include "qapi/error.h" |
| 22 | #include "qemu/queue.h" |
| 23 | #include "trace.h" |
| 24 | #include "nbd-internal.h" |
| 25 | #include "qemu/cutils.h" |
| 26 | |
| 27 | /* Definitions for opaque data types */ |
| 28 | |
| 29 | static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); |
| 30 | |
| 31 | /* That's all folks */ |
| 32 | |
| 33 | /* Basic flow for negotiation |
| 34 | |
| 35 | Server Client |
| 36 | Negotiate |
| 37 | |
| 38 | or |
| 39 | |
| 40 | Server Client |
| 41 | Negotiate #1 |
| 42 | Option |
| 43 | Negotiate #2 |
| 44 | |
| 45 | ---- |
| 46 | |
| 47 | followed by |
| 48 | |
| 49 | Server Client |
| 50 | Request |
| 51 | Response |
| 52 | Request |
| 53 | Response |
| 54 | ... |
| 55 | ... |
| 56 | Request (type == 2) |
| 57 | |
| 58 | */ |
| 59 | |
| 60 | /* Send an option request. |
| 61 | * |
| 62 | * The request is for option @opt, with @data containing @len bytes of |
| 63 | * additional payload for the request (@len may be -1 to treat @data as |
| 64 | * a C string; and @data may be NULL if @len is 0). |
| 65 | * Return 0 if successful, -1 with errp set if it is impossible to |
| 66 | * continue. */ |
| 67 | static int nbd_send_option_request(QIOChannel *ioc, uint32_t opt, |
| 68 | uint32_t len, const char *data, |
| 69 | Error **errp) |
| 70 | { |
| 71 | ERRP_GUARD(); |
| 72 | NBDOption req; |
| 73 | QEMU_BUILD_BUG_ON(sizeof(req) != 16); |
| 74 | |
| 75 | if (len == -1) { |
| 76 | req.length = len = strlen(data); |
| 77 | } |
| 78 | trace_nbd_send_option_request(opt, nbd_opt_lookup(opt), len); |
| 79 | |
| 80 | stq_be_p(&req.magic, NBD_OPTS_MAGIC); |
| 81 | stl_be_p(&req.option, opt); |
| 82 | stl_be_p(&req.length, len); |
| 83 | |
| 84 | if (nbd_write(ioc, &req, sizeof(req), errp) < 0) { |
| 85 | error_prepend(errp, "Failed to send option request header: "); |
| 86 | return -1; |
| 87 | } |
| 88 | |
| 89 | if (len && nbd_write(ioc, (char *) data, len, errp) < 0) { |
| 90 | error_prepend(errp, "Failed to send option request data: "); |
| 91 | return -1; |
| 92 | } |
| 93 | |
| 94 | return 0; |
| 95 | } |
| 96 | |
| 97 | /* Send NBD_OPT_ABORT as a courtesy to let the server know that we are |
| 98 | * not going to attempt further negotiation. */ |
| 99 | static void nbd_send_opt_abort(QIOChannel *ioc) |
| 100 | { |
| 101 | /* Technically, a compliant server is supposed to reply to us; but |
| 102 | * older servers disconnected instead. At any rate, we're allowed |
| 103 | * to disconnect without waiting for the server reply, so we don't |
| 104 | * even care if the request makes it to the server, let alone |
| 105 | * waiting around for whether the server replies. */ |
| 106 | nbd_send_option_request(ioc, NBD_OPT_ABORT, 0, NULL, NULL); |
| 107 | } |
| 108 | |
| 109 | |
| 110 | /* Receive the header of an option reply, which should match the given |
| 111 | * opt. Read through the length field, but NOT the length bytes of |
| 112 | * payload. Return 0 if successful, -1 with errp set if it is |
| 113 | * impossible to continue. */ |
| 114 | static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt, |
| 115 | NBDOptionReply *reply, Error **errp) |
| 116 | { |
| 117 | QEMU_BUILD_BUG_ON(sizeof(*reply) != 20); |
| 118 | if (nbd_read(ioc, reply, sizeof(*reply), "option reply", errp) < 0) { |
| 119 | nbd_send_opt_abort(ioc); |
| 120 | return -1; |
| 121 | } |
| 122 | reply->magic = be64_to_cpu(reply->magic); |
| 123 | reply->option = be32_to_cpu(reply->option); |
| 124 | reply->type = be32_to_cpu(reply->type); |
| 125 | reply->length = be32_to_cpu(reply->length); |
| 126 | |
| 127 | trace_nbd_receive_option_reply(reply->option, nbd_opt_lookup(reply->option), |
| 128 | reply->type, nbd_rep_lookup(reply->type), |
| 129 | reply->length); |
| 130 | |
| 131 | if (reply->magic != NBD_REP_MAGIC) { |
| 132 | error_setg(errp, "Unexpected option reply magic"); |
| 133 | nbd_send_opt_abort(ioc); |
| 134 | return -1; |
| 135 | } |
| 136 | if (reply->option != opt) { |
| 137 | error_setg(errp, "Unexpected option type %u (%s), expected %u (%s)", |
| 138 | reply->option, nbd_opt_lookup(reply->option), |
| 139 | opt, nbd_opt_lookup(opt)); |
| 140 | nbd_send_opt_abort(ioc); |
| 141 | return -1; |
| 142 | } |
| 143 | return 0; |
| 144 | } |
| 145 | |
| 146 | /* |
| 147 | * If reply represents success, return 1 without further action. If |
| 148 | * reply represents an error, consume the optional payload of the |
| 149 | * packet on ioc. Then return 0 for unsupported (so the client can |
| 150 | * fall back to other approaches), where @strict determines if only |
| 151 | * ERR_UNSUP or all errors fit that category, or -1 with errp set for |
| 152 | * other errors. |
| 153 | */ |
| 154 | static int nbd_handle_reply_err(QIOChannel *ioc, NBDOptionReply *reply, |
| 155 | bool strict, Error **errp) |
| 156 | { |
| 157 | ERRP_GUARD(); |
| 158 | g_autofree char *msg = NULL; |
| 159 | |
| 160 | if (!(reply->type & (1 << 31))) { |
| 161 | return 1; |
| 162 | } |
| 163 | |
| 164 | if (reply->length) { |
| 165 | if (reply->length > NBD_MAX_BUFFER_SIZE) { |
| 166 | error_setg(errp, "server error %" PRIu32 |
| 167 | " (%s) message is too long", |
| 168 | reply->type, nbd_rep_lookup(reply->type)); |
| 169 | goto err; |
| 170 | } |
| 171 | msg = g_malloc(reply->length + 1); |
| 172 | if (nbd_read(ioc, msg, reply->length, NULL, errp) < 0) { |
| 173 | error_prepend(errp, "Failed to read option error %" PRIu32 |
| 174 | " (%s) message: ", |
| 175 | reply->type, nbd_rep_lookup(reply->type)); |
| 176 | goto err; |
| 177 | } |
| 178 | msg[reply->length] = '\0'; |
| 179 | trace_nbd_server_error_msg(reply->type, |
| 180 | nbd_reply_type_lookup(reply->type), msg); |
| 181 | } |
| 182 | |
| 183 | if (reply->type == NBD_REP_ERR_UNSUP || !strict) { |
| 184 | trace_nbd_reply_err_ignored(reply->option, |
| 185 | nbd_opt_lookup(reply->option), |
| 186 | reply->type, nbd_rep_lookup(reply->type)); |
| 187 | return 0; |
| 188 | } |
| 189 | |
| 190 | switch (reply->type) { |
| 191 | case NBD_REP_ERR_POLICY: |
| 192 | error_setg(errp, "Denied by server for option %" PRIu32 " (%s)", |
| 193 | reply->option, nbd_opt_lookup(reply->option)); |
| 194 | break; |
| 195 | |
| 196 | case NBD_REP_ERR_INVALID: |
| 197 | error_setg(errp, "Invalid parameters for option %" PRIu32 " (%s)", |
| 198 | reply->option, nbd_opt_lookup(reply->option)); |
| 199 | break; |
| 200 | |
| 201 | case NBD_REP_ERR_PLATFORM: |
| 202 | error_setg(errp, "Server lacks support for option %" PRIu32 " (%s)", |
| 203 | reply->option, nbd_opt_lookup(reply->option)); |
| 204 | break; |
| 205 | |
| 206 | case NBD_REP_ERR_TLS_REQD: |
| 207 | error_setg(errp, "TLS negotiation required before option %" PRIu32 |
| 208 | " (%s)", reply->option, nbd_opt_lookup(reply->option)); |
| 209 | error_append_hint(errp, "Did you forget a valid tls-creds?\n"); |
| 210 | break; |
| 211 | |
| 212 | case NBD_REP_ERR_UNKNOWN: |
| 213 | error_setg(errp, "Requested export not available"); |
| 214 | break; |
| 215 | |
| 216 | case NBD_REP_ERR_SHUTDOWN: |
| 217 | error_setg(errp, "Server shutting down before option %" PRIu32 " (%s)", |
| 218 | reply->option, nbd_opt_lookup(reply->option)); |
| 219 | break; |
| 220 | |
| 221 | case NBD_REP_ERR_BLOCK_SIZE_REQD: |
| 222 | error_setg(errp, "Server requires INFO_BLOCK_SIZE for option %" PRIu32 |
| 223 | " (%s)", reply->option, nbd_opt_lookup(reply->option)); |
| 224 | break; |
| 225 | |
| 226 | default: |
| 227 | error_setg(errp, "Unknown error code when asking for option %" PRIu32 |
| 228 | " (%s)", reply->option, nbd_opt_lookup(reply->option)); |
| 229 | break; |
| 230 | } |
| 231 | |
| 232 | if (msg) { |
| 233 | error_append_hint(errp, "server reported: %s\n", msg); |
| 234 | } |
| 235 | |
| 236 | err: |
| 237 | nbd_send_opt_abort(ioc); |
| 238 | return -1; |
| 239 | } |
| 240 | |
| 241 | /* nbd_receive_list: |
| 242 | * Process another portion of the NBD_OPT_LIST reply, populating any |
| 243 | * name received into *@name. If @description is non-NULL, and the |
| 244 | * server provided a description, that is also populated. The caller |
| 245 | * must eventually call g_free() on success. |
| 246 | * Returns 1 if name and description were set and iteration must continue, |
| 247 | * 0 if iteration is complete (including if OPT_LIST unsupported), |
| 248 | * -1 with @errp set if an unrecoverable error occurred. |
| 249 | */ |
| 250 | static int nbd_receive_list(QIOChannel *ioc, char **name, char **description, |
| 251 | Error **errp) |
| 252 | { |
| 253 | NBDOptionReply reply; |
| 254 | uint32_t len; |
| 255 | uint32_t namelen; |
| 256 | g_autofree char *local_name = NULL; |
| 257 | g_autofree char *local_desc = NULL; |
| 258 | int error; |
| 259 | |
| 260 | if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) { |
| 261 | return -1; |
| 262 | } |
| 263 | error = nbd_handle_reply_err(ioc, &reply, true, errp); |
| 264 | if (error <= 0) { |
| 265 | return error; |
| 266 | } |
| 267 | len = reply.length; |
| 268 | |
| 269 | if (reply.type == NBD_REP_ACK) { |
| 270 | if (len != 0) { |
| 271 | error_setg(errp, "length too long for option end"); |
| 272 | nbd_send_opt_abort(ioc); |
| 273 | return -1; |
| 274 | } |
| 275 | return 0; |
| 276 | } else if (reply.type != NBD_REP_SERVER) { |
| 277 | error_setg(errp, "Unexpected reply type %u (%s), expected %u (%s)", |
| 278 | reply.type, nbd_rep_lookup(reply.type), |
| 279 | NBD_REP_SERVER, nbd_rep_lookup(NBD_REP_SERVER)); |
| 280 | nbd_send_opt_abort(ioc); |
| 281 | return -1; |
| 282 | } |
| 283 | |
| 284 | if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) { |
| 285 | error_setg(errp, "incorrect option length %" PRIu32, len); |
| 286 | nbd_send_opt_abort(ioc); |
| 287 | return -1; |
| 288 | } |
| 289 | if (nbd_read32(ioc, &namelen, "option name length", errp) < 0) { |
| 290 | nbd_send_opt_abort(ioc); |
| 291 | return -1; |
| 292 | } |
| 293 | len -= sizeof(namelen); |
| 294 | if (len < namelen || namelen > NBD_MAX_STRING_SIZE) { |
| 295 | error_setg(errp, "incorrect name length in server's list response"); |
| 296 | nbd_send_opt_abort(ioc); |
| 297 | return -1; |
| 298 | } |
| 299 | |
| 300 | local_name = g_malloc(namelen + 1); |
| 301 | if (nbd_read(ioc, local_name, namelen, "export name", errp) < 0) { |
| 302 | nbd_send_opt_abort(ioc); |
| 303 | return -1; |
| 304 | } |
| 305 | local_name[namelen] = '\0'; |
| 306 | len -= namelen; |
| 307 | if (len) { |
| 308 | if (len > NBD_MAX_STRING_SIZE) { |
| 309 | error_setg(errp, "incorrect description length in server's " |
| 310 | "list response"); |
| 311 | nbd_send_opt_abort(ioc); |
| 312 | return -1; |
| 313 | } |
| 314 | local_desc = g_malloc(len + 1); |
| 315 | if (nbd_read(ioc, local_desc, len, "export description", errp) < 0) { |
| 316 | nbd_send_opt_abort(ioc); |
| 317 | return -1; |
| 318 | } |
| 319 | local_desc[len] = '\0'; |
| 320 | } |
| 321 | |
| 322 | trace_nbd_receive_list(local_name, local_desc ?: ""); |
| 323 | *name = g_steal_pointer(&local_name); |
| 324 | if (description) { |
| 325 | *description = g_steal_pointer(&local_desc); |
| 326 | } |
| 327 | return 1; |
| 328 | } |
| 329 | |
| 330 | |
| 331 | /* |
| 332 | * nbd_opt_info_or_go: |
| 333 | * Send option for NBD_OPT_INFO or NBD_OPT_GO and parse the reply. |
| 334 | * Returns -1 if the option proves the export @info->name cannot be |
| 335 | * used, 0 if the option is unsupported (fall back to NBD_OPT_LIST and |
| 336 | * NBD_OPT_EXPORT_NAME in that case), and > 0 if the export is good to |
| 337 | * go (with the rest of @info populated). |
| 338 | */ |
| 339 | static int nbd_opt_info_or_go(QIOChannel *ioc, uint32_t opt, |
| 340 | NBDExportInfo *info, Error **errp) |
| 341 | { |
| 342 | ERRP_GUARD(); |
| 343 | NBDOptionReply reply; |
| 344 | uint32_t len = strlen(info->name); |
| 345 | uint16_t type; |
| 346 | int error; |
| 347 | char *buf; |
| 348 | |
| 349 | /* The protocol requires that the server send NBD_INFO_EXPORT with |
| 350 | * a non-zero flags (at least NBD_FLAG_HAS_FLAGS must be set); so |
| 351 | * flags still 0 is a witness of a broken server. */ |
| 352 | info->flags = 0; |
| 353 | |
| 354 | assert(opt == NBD_OPT_GO || opt == NBD_OPT_INFO); |
| 355 | trace_nbd_opt_info_go_start(nbd_opt_lookup(opt), info->name); |
| 356 | buf = g_malloc(4 + len + 2 + 2 * info->request_sizes + 1); |
| 357 | stl_be_p(buf, len); |
| 358 | memcpy(buf + 4, info->name, len); |
| 359 | /* At most one request, everything else up to server */ |
| 360 | stw_be_p(buf + 4 + len, info->request_sizes); |
| 361 | if (info->request_sizes) { |
| 362 | stw_be_p(buf + 4 + len + 2, NBD_INFO_BLOCK_SIZE); |
| 363 | } |
| 364 | error = nbd_send_option_request(ioc, opt, |
| 365 | 4 + len + 2 + 2 * info->request_sizes, |
| 366 | buf, errp); |
| 367 | g_free(buf); |
| 368 | if (error < 0) { |
| 369 | return -1; |
| 370 | } |
| 371 | |
| 372 | while (1) { |
| 373 | if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) { |
| 374 | return -1; |
| 375 | } |
| 376 | error = nbd_handle_reply_err(ioc, &reply, true, errp); |
| 377 | if (error <= 0) { |
| 378 | return error; |
| 379 | } |
| 380 | len = reply.length; |
| 381 | |
| 382 | if (reply.type == NBD_REP_ACK) { |
| 383 | /* |
| 384 | * Server is done sending info, and moved into transmission |
| 385 | * phase for NBD_OPT_GO, but make sure it sent flags |
| 386 | */ |
| 387 | if (len) { |
| 388 | error_setg(errp, "server sent invalid NBD_REP_ACK"); |
| 389 | return -1; |
| 390 | } |
| 391 | if (!info->flags) { |
| 392 | error_setg(errp, "broken server omitted NBD_INFO_EXPORT"); |
| 393 | return -1; |
| 394 | } |
| 395 | trace_nbd_opt_info_go_success(nbd_opt_lookup(opt)); |
| 396 | return 1; |
| 397 | } |
| 398 | if (reply.type != NBD_REP_INFO) { |
| 399 | error_setg(errp, "unexpected reply type %u (%s), expected %u (%s)", |
| 400 | reply.type, nbd_rep_lookup(reply.type), |
| 401 | NBD_REP_INFO, nbd_rep_lookup(NBD_REP_INFO)); |
| 402 | nbd_send_opt_abort(ioc); |
| 403 | return -1; |
| 404 | } |
| 405 | if (len < sizeof(type)) { |
| 406 | error_setg(errp, "NBD_REP_INFO length %" PRIu32 " is too short", |
| 407 | len); |
| 408 | nbd_send_opt_abort(ioc); |
| 409 | return -1; |
| 410 | } |
| 411 | if (nbd_read16(ioc, &type, "info type", errp) < 0) { |
| 412 | nbd_send_opt_abort(ioc); |
| 413 | return -1; |
| 414 | } |
| 415 | len -= sizeof(type); |
| 416 | switch (type) { |
| 417 | case NBD_INFO_EXPORT: |
| 418 | if (len != sizeof(info->size) + sizeof(info->flags)) { |
| 419 | error_setg(errp, "remaining export info len %" PRIu32 |
| 420 | " is unexpected size", len); |
| 421 | nbd_send_opt_abort(ioc); |
| 422 | return -1; |
| 423 | } |
| 424 | if (nbd_read64(ioc, &info->size, "info size", errp) < 0) { |
| 425 | nbd_send_opt_abort(ioc); |
| 426 | return -1; |
| 427 | } |
| 428 | if (nbd_read16(ioc, &info->flags, "info flags", errp) < 0) { |
| 429 | nbd_send_opt_abort(ioc); |
| 430 | return -1; |
| 431 | } |
| 432 | if (info->min_block && |
| 433 | !QEMU_IS_ALIGNED(info->size, info->min_block)) { |
| 434 | error_setg(errp, "export size %" PRIu64 " is not multiple of " |
| 435 | "minimum block size %" PRIu32, info->size, |
| 436 | info->min_block); |
| 437 | nbd_send_opt_abort(ioc); |
| 438 | return -1; |
| 439 | } |
| 440 | trace_nbd_receive_negotiate_size_flags(info->size, info->flags); |
| 441 | break; |
| 442 | |
| 443 | case NBD_INFO_BLOCK_SIZE: |
| 444 | if (len != sizeof(info->min_block) * 3) { |
| 445 | error_setg(errp, "remaining export info len %" PRIu32 |
| 446 | " is unexpected size", len); |
| 447 | nbd_send_opt_abort(ioc); |
| 448 | return -1; |
| 449 | } |
| 450 | if (nbd_read32(ioc, &info->min_block, "info minimum block size", |
| 451 | errp) < 0) { |
| 452 | nbd_send_opt_abort(ioc); |
| 453 | return -1; |
| 454 | } |
| 455 | if (!is_power_of_2(info->min_block)) { |
| 456 | error_setg(errp, "server minimum block size %" PRIu32 |
| 457 | " is not a power of two", info->min_block); |
| 458 | nbd_send_opt_abort(ioc); |
| 459 | return -1; |
| 460 | } |
| 461 | if (nbd_read32(ioc, &info->opt_block, "info preferred block size", |
| 462 | errp) < 0) |
| 463 | { |
| 464 | nbd_send_opt_abort(ioc); |
| 465 | return -1; |
| 466 | } |
| 467 | if (!is_power_of_2(info->opt_block) || |
| 468 | info->opt_block < info->min_block) { |
| 469 | error_setg(errp, "server preferred block size %" PRIu32 |
| 470 | " is not valid", info->opt_block); |
| 471 | nbd_send_opt_abort(ioc); |
| 472 | return -1; |
| 473 | } |
| 474 | if (nbd_read32(ioc, &info->max_block, "info maximum block size", |
| 475 | errp) < 0) |
| 476 | { |
| 477 | nbd_send_opt_abort(ioc); |
| 478 | return -1; |
| 479 | } |
| 480 | if (info->max_block < info->min_block) { |
| 481 | error_setg(errp, "server maximum block size %" PRIu32 |
| 482 | " is not valid", info->max_block); |
| 483 | nbd_send_opt_abort(ioc); |
| 484 | return -1; |
| 485 | } |
| 486 | trace_nbd_opt_info_block_size(info->min_block, info->opt_block, |
| 487 | info->max_block); |
| 488 | break; |
| 489 | |
| 490 | default: |
| 491 | /* |
| 492 | * Not worth the bother to check if NBD_INFO_NAME or |
| 493 | * NBD_INFO_DESCRIPTION exceed NBD_MAX_STRING_SIZE. |
| 494 | */ |
| 495 | trace_nbd_opt_info_unknown(type, nbd_info_lookup(type)); |
| 496 | if (nbd_drop(ioc, len, errp) < 0) { |
| 497 | error_prepend(errp, "Failed to read info payload: "); |
| 498 | nbd_send_opt_abort(ioc); |
| 499 | return -1; |
| 500 | } |
| 501 | break; |
| 502 | } |
| 503 | } |
| 504 | } |
| 505 | |
| 506 | /* Return -1 on failure, 0 if wantname is an available export. */ |
| 507 | static int nbd_receive_query_exports(QIOChannel *ioc, |
| 508 | const char *wantname, |
| 509 | Error **errp) |
| 510 | { |
| 511 | bool list_empty = true; |
| 512 | bool found_export = false; |
| 513 | |
| 514 | trace_nbd_receive_query_exports_start(wantname); |
| 515 | if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) { |
| 516 | return -1; |
| 517 | } |
| 518 | |
| 519 | while (1) { |
| 520 | char *name; |
| 521 | int ret = nbd_receive_list(ioc, &name, NULL, errp); |
| 522 | |
| 523 | if (ret < 0) { |
| 524 | /* Server gave unexpected reply */ |
| 525 | return -1; |
| 526 | } else if (ret == 0) { |
| 527 | /* Done iterating. */ |
| 528 | if (list_empty) { |
| 529 | /* |
| 530 | * We don't have enough context to tell a server that |
| 531 | * sent an empty list apart from a server that does |
| 532 | * not support the list command; but as this function |
| 533 | * is just used to trigger a nicer error message |
| 534 | * before trying NBD_OPT_EXPORT_NAME, assume the |
| 535 | * export is available. |
| 536 | */ |
| 537 | return 0; |
| 538 | } else if (!found_export) { |
| 539 | error_setg(errp, "No export with name '%s' available", |
| 540 | wantname); |
| 541 | nbd_send_opt_abort(ioc); |
| 542 | return -1; |
| 543 | } |
| 544 | trace_nbd_receive_query_exports_success(wantname); |
| 545 | return 0; |
| 546 | } |
| 547 | list_empty = false; |
| 548 | if (!strcmp(name, wantname)) { |
| 549 | found_export = true; |
| 550 | } |
| 551 | g_free(name); |
| 552 | } |
| 553 | } |
| 554 | |
| 555 | /* |
| 556 | * nbd_request_simple_option: Send an option request, and parse the reply. |
| 557 | * @strict controls whether ERR_UNSUP or all errors produce 0 status. |
| 558 | * return 1 for successful negotiation, |
| 559 | * 0 if operation is unsupported, |
| 560 | * -1 with errp set for any other error |
| 561 | */ |
| 562 | static int nbd_request_simple_option(QIOChannel *ioc, int opt, bool strict, |
| 563 | Error **errp) |
| 564 | { |
| 565 | NBDOptionReply reply; |
| 566 | int error; |
| 567 | |
| 568 | if (nbd_send_option_request(ioc, opt, 0, NULL, errp) < 0) { |
| 569 | return -1; |
| 570 | } |
| 571 | |
| 572 | if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) { |
| 573 | return -1; |
| 574 | } |
| 575 | error = nbd_handle_reply_err(ioc, &reply, strict, errp); |
| 576 | if (error <= 0) { |
| 577 | return error; |
| 578 | } |
| 579 | |
| 580 | if (reply.type != NBD_REP_ACK) { |
| 581 | error_setg(errp, "Server answered option %d (%s) with unexpected " |
| 582 | "reply %" PRIu32 " (%s)", opt, nbd_opt_lookup(opt), |
| 583 | reply.type, nbd_rep_lookup(reply.type)); |
| 584 | nbd_send_opt_abort(ioc); |
| 585 | return -1; |
| 586 | } |
| 587 | |
| 588 | if (reply.length != 0) { |
| 589 | error_setg(errp, "Option %d ('%s') response length is %" PRIu32 |
| 590 | " (it should be zero)", opt, nbd_opt_lookup(opt), |
| 591 | reply.length); |
| 592 | nbd_send_opt_abort(ioc); |
| 593 | return -1; |
| 594 | } |
| 595 | |
| 596 | return 1; |
| 597 | } |
| 598 | |
| 599 | /* Callback to learn when QIO TLS upgrade is complete */ |
| 600 | struct NBDTLSClientHandshakeData { |
| 601 | bool complete; |
| 602 | Error *error; |
| 603 | GMainLoop *loop; |
| 604 | }; |
| 605 | |
| 606 | static void nbd_client_tls_handshake(QIOTask *task, void *opaque) |
| 607 | { |
| 608 | struct NBDTLSClientHandshakeData *data = opaque; |
| 609 | |
| 610 | qio_task_propagate_error(task, &data->error); |
| 611 | data->complete = true; |
| 612 | if (data->loop) { |
| 613 | g_main_loop_quit(data->loop); |
| 614 | } |
| 615 | } |
| 616 | |
| 617 | static QIOChannel *nbd_receive_starttls(QIOChannel *ioc, |
| 618 | QCryptoTLSCreds *tlscreds, |
| 619 | const char *hostname, Error **errp) |
| 620 | { |
| 621 | int ret; |
| 622 | QIOChannelTLS *tioc; |
| 623 | struct NBDTLSClientHandshakeData data = { 0 }; |
| 624 | |
| 625 | ret = nbd_request_simple_option(ioc, NBD_OPT_STARTTLS, true, errp); |
| 626 | if (ret <= 0) { |
| 627 | if (ret == 0) { |
| 628 | error_setg(errp, "Server don't support STARTTLS option"); |
| 629 | nbd_send_opt_abort(ioc); |
| 630 | } |
| 631 | return NULL; |
| 632 | } |
| 633 | |
| 634 | trace_nbd_receive_starttls_new_client(); |
| 635 | tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp); |
| 636 | if (!tioc) { |
| 637 | return NULL; |
| 638 | } |
| 639 | qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-client-tls"); |
| 640 | trace_nbd_receive_starttls_tls_handshake(); |
| 641 | qio_channel_tls_handshake(tioc, |
| 642 | nbd_client_tls_handshake, |
| 643 | &data, |
| 644 | NULL, |
| 645 | NULL); |
| 646 | |
| 647 | if (!data.complete) { |
| 648 | data.loop = g_main_loop_new(g_main_context_default(), FALSE); |
| 649 | g_main_loop_run(data.loop); |
| 650 | assert(data.complete); |
| 651 | g_main_loop_unref(data.loop); |
| 652 | } |
| 653 | |
| 654 | if (data.error) { |
| 655 | error_propagate(errp, data.error); |
| 656 | object_unref(OBJECT(tioc)); |
| 657 | return NULL; |
| 658 | } |
| 659 | |
| 660 | return QIO_CHANNEL(tioc); |
| 661 | } |
| 662 | |
| 663 | /* |
| 664 | * nbd_send_meta_query: |
| 665 | * Send 0 or 1 set/list meta context queries. |
| 666 | * Return 0 on success, -1 with errp set for any error |
| 667 | */ |
| 668 | static int nbd_send_meta_query(QIOChannel *ioc, uint32_t opt, |
| 669 | const char *export, const char *query, |
| 670 | Error **errp) |
| 671 | { |
| 672 | int ret; |
| 673 | uint32_t export_len; |
| 674 | uint32_t queries = !!query; |
| 675 | uint32_t query_len = 0; |
| 676 | uint32_t data_len; |
| 677 | char *data; |
| 678 | char *p; |
| 679 | |
| 680 | assert(strnlen(export, NBD_MAX_STRING_SIZE + 1) <= NBD_MAX_STRING_SIZE); |
| 681 | export_len = strlen(export); |
| 682 | data_len = sizeof(export_len) + export_len + sizeof(queries); |
| 683 | if (query) { |
| 684 | assert(strnlen(query, NBD_MAX_STRING_SIZE + 1) <= NBD_MAX_STRING_SIZE); |
| 685 | query_len = strlen(query); |
| 686 | data_len += sizeof(query_len) + query_len; |
| 687 | } else { |
| 688 | assert(opt == NBD_OPT_LIST_META_CONTEXT); |
| 689 | } |
| 690 | p = data = g_malloc(data_len); |
| 691 | |
| 692 | trace_nbd_opt_meta_request(nbd_opt_lookup(opt), query ?: "(all)", export); |
| 693 | stl_be_p(p, export_len); |
| 694 | memcpy(p += sizeof(export_len), export, export_len); |
| 695 | stl_be_p(p += export_len, queries); |
| 696 | if (query) { |
| 697 | stl_be_p(p += sizeof(queries), query_len); |
| 698 | memcpy(p += sizeof(query_len), query, query_len); |
| 699 | } |
| 700 | |
| 701 | ret = nbd_send_option_request(ioc, opt, data_len, data, errp); |
| 702 | g_free(data); |
| 703 | return ret; |
| 704 | } |
| 705 | |
| 706 | /* |
| 707 | * nbd_receive_one_meta_context: |
| 708 | * Called in a loop to receive and trace one set/list meta context reply. |
| 709 | * Pass non-NULL @name or @id to collect results back to the caller, which |
| 710 | * must eventually call g_free(). |
| 711 | * return 1 if name is set and iteration must continue, |
| 712 | * 0 if iteration is complete (including if option is unsupported), |
| 713 | * -1 with errp set for any error |
| 714 | */ |
| 715 | static int nbd_receive_one_meta_context(QIOChannel *ioc, |
| 716 | uint32_t opt, |
| 717 | char **name, |
| 718 | uint32_t *id, |
| 719 | Error **errp) |
| 720 | { |
| 721 | int ret; |
| 722 | NBDOptionReply reply; |
| 723 | char *local_name = NULL; |
| 724 | uint32_t local_id; |
| 725 | |
| 726 | if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) { |
| 727 | return -1; |
| 728 | } |
| 729 | |
| 730 | ret = nbd_handle_reply_err(ioc, &reply, false, errp); |
| 731 | if (ret <= 0) { |
| 732 | return ret; |
| 733 | } |
| 734 | |
| 735 | if (reply.type == NBD_REP_ACK) { |
| 736 | if (reply.length != 0) { |
| 737 | error_setg(errp, "Unexpected length to ACK response"); |
| 738 | nbd_send_opt_abort(ioc); |
| 739 | return -1; |
| 740 | } |
| 741 | return 0; |
| 742 | } else if (reply.type != NBD_REP_META_CONTEXT) { |
| 743 | error_setg(errp, "Unexpected reply type %u (%s), expected %u (%s)", |
| 744 | reply.type, nbd_rep_lookup(reply.type), |
| 745 | NBD_REP_META_CONTEXT, nbd_rep_lookup(NBD_REP_META_CONTEXT)); |
| 746 | nbd_send_opt_abort(ioc); |
| 747 | return -1; |
| 748 | } |
| 749 | |
| 750 | if (reply.length <= sizeof(local_id) || |
| 751 | reply.length > NBD_MAX_BUFFER_SIZE) { |
| 752 | error_setg(errp, "Failed to negotiate meta context, server " |
| 753 | "answered with unexpected length %" PRIu32, |
| 754 | reply.length); |
| 755 | nbd_send_opt_abort(ioc); |
| 756 | return -1; |
| 757 | } |
| 758 | |
| 759 | if (nbd_read32(ioc, &local_id, "context id", errp) < 0) { |
| 760 | return -1; |
| 761 | } |
| 762 | |
| 763 | reply.length -= sizeof(local_id); |
| 764 | local_name = g_malloc(reply.length + 1); |
| 765 | if (nbd_read(ioc, local_name, reply.length, "context name", errp) < 0) { |
| 766 | g_free(local_name); |
| 767 | return -1; |
| 768 | } |
| 769 | local_name[reply.length] = '\0'; |
| 770 | trace_nbd_opt_meta_reply(nbd_opt_lookup(opt), local_name, local_id); |
| 771 | |
| 772 | if (name) { |
| 773 | *name = local_name; |
| 774 | } else { |
| 775 | g_free(local_name); |
| 776 | } |
| 777 | if (id) { |
| 778 | *id = local_id; |
| 779 | } |
| 780 | return 1; |
| 781 | } |
| 782 | |
| 783 | /* |
| 784 | * nbd_negotiate_simple_meta_context: |
| 785 | * Request the server to set the meta context for export @info->name |
| 786 | * using @info->x_dirty_bitmap with a fallback to "base:allocation", |
| 787 | * setting @info->context_id to the resulting id. Fail if the server |
| 788 | * responds with more than one context or with a context different |
| 789 | * than the query. |
| 790 | * return 1 for successful negotiation, |
| 791 | * 0 if operation is unsupported, |
| 792 | * -1 with errp set for any other error |
| 793 | */ |
| 794 | static int nbd_negotiate_simple_meta_context(QIOChannel *ioc, |
| 795 | NBDExportInfo *info, |
| 796 | Error **errp) |
| 797 | { |
| 798 | /* |
| 799 | * TODO: Removing the x_dirty_bitmap hack will mean refactoring |
| 800 | * this function to request and store ids for multiple contexts |
| 801 | * (both base:allocation and a dirty bitmap), at which point this |
| 802 | * function should lose the term _simple. |
| 803 | */ |
| 804 | int ret; |
| 805 | const char *context = info->x_dirty_bitmap ?: "base:allocation"; |
| 806 | bool received = false; |
| 807 | char *name = NULL; |
| 808 | |
| 809 | if (nbd_send_meta_query(ioc, NBD_OPT_SET_META_CONTEXT, |
| 810 | info->name, context, errp) < 0) { |
| 811 | return -1; |
| 812 | } |
| 813 | |
| 814 | ret = nbd_receive_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT, |
| 815 | &name, &info->context_id, errp); |
| 816 | if (ret < 0) { |
| 817 | return -1; |
| 818 | } |
| 819 | if (ret == 1) { |
| 820 | if (strcmp(context, name)) { |
| 821 | error_setg(errp, "Failed to negotiate meta context '%s', server " |
| 822 | "answered with different context '%s'", context, |
| 823 | name); |
| 824 | g_free(name); |
| 825 | nbd_send_opt_abort(ioc); |
| 826 | return -1; |
| 827 | } |
| 828 | g_free(name); |
| 829 | received = true; |
| 830 | |
| 831 | ret = nbd_receive_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT, |
| 832 | NULL, NULL, errp); |
| 833 | if (ret < 0) { |
| 834 | return -1; |
| 835 | } |
| 836 | } |
| 837 | if (ret != 0) { |
| 838 | error_setg(errp, "Server answered with more than one context"); |
| 839 | nbd_send_opt_abort(ioc); |
| 840 | return -1; |
| 841 | } |
| 842 | return received; |
| 843 | } |
| 844 | |
| 845 | /* |
| 846 | * nbd_list_meta_contexts: |
| 847 | * Request the server to list all meta contexts for export @info->name. |
| 848 | * return 0 if list is complete (even if empty), |
| 849 | * -1 with errp set for any error |
| 850 | */ |
| 851 | static int nbd_list_meta_contexts(QIOChannel *ioc, |
| 852 | NBDExportInfo *info, |
| 853 | Error **errp) |
| 854 | { |
| 855 | int ret; |
| 856 | int seen_any = false; |
| 857 | int seen_qemu = false; |
| 858 | |
| 859 | if (nbd_send_meta_query(ioc, NBD_OPT_LIST_META_CONTEXT, |
| 860 | info->name, NULL, errp) < 0) { |
| 861 | return -1; |
| 862 | } |
| 863 | |
| 864 | while (1) { |
| 865 | char *context; |
| 866 | |
| 867 | ret = nbd_receive_one_meta_context(ioc, NBD_OPT_LIST_META_CONTEXT, |
| 868 | &context, NULL, errp); |
| 869 | if (ret == 0 && seen_any && !seen_qemu) { |
| 870 | /* |
| 871 | * Work around qemu 3.0 bug: the server forgot to send |
| 872 | * "qemu:" replies to 0 queries. If we saw at least one |
| 873 | * reply (probably base:allocation), but none of them were |
| 874 | * qemu:, then run a more specific query to make sure. |
| 875 | */ |
| 876 | seen_qemu = true; |
| 877 | if (nbd_send_meta_query(ioc, NBD_OPT_LIST_META_CONTEXT, |
| 878 | info->name, "qemu:", errp) < 0) { |
| 879 | return -1; |
| 880 | } |
| 881 | continue; |
| 882 | } |
| 883 | if (ret <= 0) { |
| 884 | return ret; |
| 885 | } |
| 886 | seen_any = true; |
| 887 | seen_qemu |= strstart(context, "qemu:", NULL); |
| 888 | info->contexts = g_renew(char *, info->contexts, ++info->n_contexts); |
| 889 | info->contexts[info->n_contexts - 1] = context; |
| 890 | } |
| 891 | } |
| 892 | |
| 893 | /* |
| 894 | * nbd_start_negotiate: |
| 895 | * Start the handshake to the server. After a positive return, the server |
| 896 | * is ready to accept additional NBD_OPT requests. |
| 897 | * Returns: negative errno: failure talking to server |
| 898 | * non-negative: enum NBDMode describing server abilities |
| 899 | */ |
| 900 | static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, |
| 901 | const char *hostname, QIOChannel **outioc, |
| 902 | NBDMode max_mode, bool *zeroes, |
| 903 | Error **errp) |
| 904 | { |
| 905 | ERRP_GUARD(); |
| 906 | uint64_t magic; |
| 907 | |
| 908 | trace_nbd_start_negotiate(tlscreds, hostname ? hostname : "<null>"); |
| 909 | |
| 910 | if (zeroes) { |
| 911 | *zeroes = true; |
| 912 | } |
| 913 | if (outioc) { |
| 914 | *outioc = NULL; |
| 915 | } |
| 916 | if (tlscreds && !outioc) { |
| 917 | error_setg(errp, "Output I/O channel required for TLS"); |
| 918 | return -EINVAL; |
| 919 | } |
| 920 | |
| 921 | if (nbd_read64(ioc, &magic, "initial magic", errp) < 0) { |
| 922 | return -EINVAL; |
| 923 | } |
| 924 | trace_nbd_receive_negotiate_magic(magic); |
| 925 | |
| 926 | if (magic != NBD_INIT_MAGIC) { |
| 927 | error_setg(errp, "Bad initial magic received: 0x%" PRIx64, magic); |
| 928 | return -EINVAL; |
| 929 | } |
| 930 | |
| 931 | if (nbd_read64(ioc, &magic, "server magic", errp) < 0) { |
| 932 | return -EINVAL; |
| 933 | } |
| 934 | trace_nbd_receive_negotiate_magic(magic); |
| 935 | |
| 936 | if (magic == NBD_OPTS_MAGIC) { |
| 937 | uint32_t clientflags = 0; |
| 938 | uint16_t globalflags; |
| 939 | bool fixedNewStyle = false; |
| 940 | |
| 941 | if (nbd_read16(ioc, &globalflags, "server flags", errp) < 0) { |
| 942 | return -EINVAL; |
| 943 | } |
| 944 | trace_nbd_receive_negotiate_server_flags(globalflags); |
| 945 | if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) { |
| 946 | fixedNewStyle = true; |
| 947 | clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE; |
| 948 | } |
| 949 | if (globalflags & NBD_FLAG_NO_ZEROES) { |
| 950 | if (zeroes) { |
| 951 | *zeroes = false; |
| 952 | } |
| 953 | clientflags |= NBD_FLAG_C_NO_ZEROES; |
| 954 | } |
| 955 | /* client requested flags */ |
| 956 | clientflags = cpu_to_be32(clientflags); |
| 957 | if (nbd_write(ioc, &clientflags, sizeof(clientflags), errp) < 0) { |
| 958 | error_prepend(errp, "Failed to send clientflags field: "); |
| 959 | return -EINVAL; |
| 960 | } |
| 961 | if (tlscreds) { |
| 962 | if (fixedNewStyle) { |
| 963 | *outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp); |
| 964 | if (!*outioc) { |
| 965 | return -EINVAL; |
| 966 | } |
| 967 | ioc = *outioc; |
| 968 | } else { |
| 969 | error_setg(errp, "Server does not support STARTTLS"); |
| 970 | return -EINVAL; |
| 971 | } |
| 972 | } |
| 973 | if (fixedNewStyle) { |
| 974 | int result = 0; |
| 975 | |
| 976 | if (max_mode >= NBD_MODE_EXTENDED) { |
| 977 | result = nbd_request_simple_option(ioc, |
| 978 | NBD_OPT_EXTENDED_HEADERS, |
| 979 | false, errp); |
| 980 | if (result) { |
| 981 | return result < 0 ? -EINVAL : NBD_MODE_EXTENDED; |
| 982 | } |
| 983 | } |
| 984 | if (max_mode >= NBD_MODE_STRUCTURED) { |
| 985 | result = nbd_request_simple_option(ioc, |
| 986 | NBD_OPT_STRUCTURED_REPLY, |
| 987 | false, errp); |
| 988 | if (result) { |
| 989 | return result < 0 ? -EINVAL : NBD_MODE_STRUCTURED; |
| 990 | } |
| 991 | } |
| 992 | return NBD_MODE_SIMPLE; |
| 993 | } else { |
| 994 | return NBD_MODE_EXPORT_NAME; |
| 995 | } |
| 996 | } else if (magic == NBD_CLIENT_MAGIC) { |
| 997 | if (tlscreds) { |
| 998 | error_setg(errp, "Server does not support STARTTLS"); |
| 999 | return -EINVAL; |
| 1000 | } |
| 1001 | return NBD_MODE_OLDSTYLE; |
| 1002 | } else { |
| 1003 | error_setg(errp, "Bad server magic received: 0x%" PRIx64, magic); |
| 1004 | return -EINVAL; |
| 1005 | } |
| 1006 | } |
| 1007 | |
| 1008 | /* |
| 1009 | * nbd_negotiate_finish_oldstyle: |
| 1010 | * Populate @info with the size and export flags from an oldstyle server, |
| 1011 | * but does not consume 124 bytes of reserved zero padding. |
| 1012 | * Returns 0 on success, -1 with @errp set on failure |
| 1013 | */ |
| 1014 | static int nbd_negotiate_finish_oldstyle(QIOChannel *ioc, NBDExportInfo *info, |
| 1015 | Error **errp) |
| 1016 | { |
| 1017 | uint32_t oldflags; |
| 1018 | |
| 1019 | if (nbd_read64(ioc, &info->size, "export length", errp) < 0) { |
| 1020 | return -EINVAL; |
| 1021 | } |
| 1022 | |
| 1023 | if (nbd_read32(ioc, &oldflags, "export flags", errp) < 0) { |
| 1024 | return -EINVAL; |
| 1025 | } |
| 1026 | if (oldflags & ~0xffff) { |
| 1027 | error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags); |
| 1028 | return -EINVAL; |
| 1029 | } |
| 1030 | info->flags = oldflags; |
| 1031 | return 0; |
| 1032 | } |
| 1033 | |
| 1034 | /* |
| 1035 | * nbd_receive_negotiate: |
| 1036 | * Connect to server, complete negotiation, and move into transmission phase. |
| 1037 | * Returns: negative errno: failure talking to server |
| 1038 | * 0: server is connected |
| 1039 | */ |
| 1040 | int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, |
| 1041 | const char *hostname, QIOChannel **outioc, |
| 1042 | NBDExportInfo *info, Error **errp) |
| 1043 | { |
| 1044 | ERRP_GUARD(); |
| 1045 | int result; |
| 1046 | bool zeroes; |
| 1047 | bool base_allocation = info->base_allocation; |
| 1048 | |
| 1049 | assert(info->name && strlen(info->name) <= NBD_MAX_STRING_SIZE); |
| 1050 | trace_nbd_receive_negotiate_name(info->name); |
| 1051 | |
| 1052 | result = nbd_start_negotiate(ioc, tlscreds, hostname, outioc, |
| 1053 | info->mode, &zeroes, errp); |
| 1054 | if (result < 0) { |
| 1055 | return result; |
| 1056 | } |
| 1057 | |
| 1058 | info->mode = result; |
| 1059 | info->base_allocation = false; |
| 1060 | if (tlscreds && *outioc) { |
| 1061 | ioc = *outioc; |
| 1062 | } |
| 1063 | |
| 1064 | switch (info->mode) { |
| 1065 | case NBD_MODE_EXTENDED: |
| 1066 | case NBD_MODE_STRUCTURED: |
| 1067 | if (base_allocation) { |
| 1068 | result = nbd_negotiate_simple_meta_context(ioc, info, errp); |
| 1069 | if (result < 0) { |
| 1070 | return -EINVAL; |
| 1071 | } |
| 1072 | info->base_allocation = result == 1; |
| 1073 | } |
| 1074 | /* fall through */ |
| 1075 | case NBD_MODE_SIMPLE: |
| 1076 | /* Try NBD_OPT_GO first - if it works, we are done (it |
| 1077 | * also gives us a good message if the server requires |
| 1078 | * TLS). If it is not available, fall back to |
| 1079 | * NBD_OPT_LIST for nicer error messages about a missing |
| 1080 | * export, then use NBD_OPT_EXPORT_NAME. */ |
| 1081 | result = nbd_opt_info_or_go(ioc, NBD_OPT_GO, info, errp); |
| 1082 | if (result < 0) { |
| 1083 | return -EINVAL; |
| 1084 | } |
| 1085 | if (result > 0) { |
| 1086 | return 0; |
| 1087 | } |
| 1088 | /* Check our desired export is present in the |
| 1089 | * server export list. Since NBD_OPT_EXPORT_NAME |
| 1090 | * cannot return an error message, running this |
| 1091 | * query gives us better error reporting if the |
| 1092 | * export name is not available. |
| 1093 | */ |
| 1094 | if (nbd_receive_query_exports(ioc, info->name, errp) < 0) { |
| 1095 | return -EINVAL; |
| 1096 | } |
| 1097 | /* fall through */ |
| 1098 | case NBD_MODE_EXPORT_NAME: |
| 1099 | /* write the export name request */ |
| 1100 | if (nbd_send_option_request(ioc, NBD_OPT_EXPORT_NAME, -1, info->name, |
| 1101 | errp) < 0) { |
| 1102 | return -EINVAL; |
| 1103 | } |
| 1104 | |
| 1105 | /* Read the response */ |
| 1106 | if (nbd_read64(ioc, &info->size, "export length", errp) < 0) { |
| 1107 | return -EINVAL; |
| 1108 | } |
| 1109 | |
| 1110 | if (nbd_read16(ioc, &info->flags, "export flags", errp) < 0) { |
| 1111 | return -EINVAL; |
| 1112 | } |
| 1113 | break; |
| 1114 | case NBD_MODE_OLDSTYLE: |
| 1115 | if (*info->name) { |
| 1116 | error_setg(errp, "Server does not support non-empty export names"); |
| 1117 | return -EINVAL; |
| 1118 | } |
| 1119 | if (nbd_negotiate_finish_oldstyle(ioc, info, errp) < 0) { |
| 1120 | return -EINVAL; |
| 1121 | } |
| 1122 | break; |
| 1123 | default: |
| 1124 | g_assert_not_reached(); |
| 1125 | } |
| 1126 | |
| 1127 | trace_nbd_receive_negotiate_size_flags(info->size, info->flags); |
| 1128 | if (zeroes && nbd_drop(ioc, 124, errp) < 0) { |
| 1129 | error_prepend(errp, "Failed to read reserved block: "); |
| 1130 | return -EINVAL; |
| 1131 | } |
| 1132 | return 0; |
| 1133 | } |
| 1134 | |
| 1135 | /* Clean up result of nbd_receive_export_list */ |
| 1136 | void nbd_free_export_list(NBDExportInfo *info, int count) |
| 1137 | { |
| 1138 | int i, j; |
| 1139 | |
| 1140 | if (!info) { |
| 1141 | return; |
| 1142 | } |
| 1143 | |
| 1144 | for (i = 0; i < count; i++) { |
| 1145 | g_free(info[i].name); |
| 1146 | g_free(info[i].description); |
| 1147 | for (j = 0; j < info[i].n_contexts; j++) { |
| 1148 | g_free(info[i].contexts[j]); |
| 1149 | } |
| 1150 | g_free(info[i].contexts); |
| 1151 | } |
| 1152 | g_free(info); |
| 1153 | } |
| 1154 | |
| 1155 | /* |
| 1156 | * nbd_receive_export_list: |
| 1157 | * Query details about a server's exports, then disconnect without |
| 1158 | * going into transmission phase. Return a count of the exports listed |
| 1159 | * in @info by the server, or -1 on error. Caller must free @info using |
| 1160 | * nbd_free_export_list(). |
| 1161 | */ |
| 1162 | int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, |
| 1163 | const char *hostname, NBDExportInfo **info, |
| 1164 | Error **errp) |
| 1165 | { |
| 1166 | int result; |
| 1167 | int count = 0; |
| 1168 | int i; |
| 1169 | int rc; |
| 1170 | int ret = -1; |
| 1171 | NBDExportInfo *array = NULL; |
| 1172 | QIOChannel *sioc = NULL; |
| 1173 | |
| 1174 | *info = NULL; |
| 1175 | result = nbd_start_negotiate(ioc, tlscreds, hostname, &sioc, |
| 1176 | NBD_MODE_EXTENDED, NULL, errp); |
| 1177 | if (tlscreds && sioc) { |
| 1178 | ioc = sioc; |
| 1179 | } |
| 1180 | if (result < 0) { |
| 1181 | goto out; |
| 1182 | } |
| 1183 | |
| 1184 | switch ((NBDMode)result) { |
| 1185 | case NBD_MODE_SIMPLE: |
| 1186 | case NBD_MODE_STRUCTURED: |
| 1187 | case NBD_MODE_EXTENDED: |
| 1188 | /* newstyle - use NBD_OPT_LIST to populate array, then try |
| 1189 | * NBD_OPT_INFO on each array member. If structured replies |
| 1190 | * are enabled, also try NBD_OPT_LIST_META_CONTEXT. */ |
| 1191 | if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) { |
| 1192 | goto out; |
| 1193 | } |
| 1194 | while (1) { |
| 1195 | char *name; |
| 1196 | char *desc; |
| 1197 | |
| 1198 | rc = nbd_receive_list(ioc, &name, &desc, errp); |
| 1199 | if (rc < 0) { |
| 1200 | goto out; |
| 1201 | } else if (rc == 0) { |
| 1202 | break; |
| 1203 | } |
| 1204 | array = g_renew(NBDExportInfo, array, ++count); |
| 1205 | memset(&array[count - 1], 0, sizeof(*array)); |
| 1206 | array[count - 1].name = name; |
| 1207 | array[count - 1].description = desc; |
| 1208 | array[count - 1].mode = result; |
| 1209 | } |
| 1210 | |
| 1211 | for (i = 0; i < count; i++) { |
| 1212 | array[i].request_sizes = true; |
| 1213 | rc = nbd_opt_info_or_go(ioc, NBD_OPT_INFO, &array[i], errp); |
| 1214 | if (rc < 0) { |
| 1215 | goto out; |
| 1216 | } else if (rc == 0) { |
| 1217 | /* |
| 1218 | * Pointless to try rest of loop. If OPT_INFO doesn't work, |
| 1219 | * it's unlikely that meta contexts work either |
| 1220 | */ |
| 1221 | break; |
| 1222 | } |
| 1223 | |
| 1224 | if (result >= NBD_MODE_STRUCTURED && |
| 1225 | nbd_list_meta_contexts(ioc, &array[i], errp) < 0) { |
| 1226 | goto out; |
| 1227 | } |
| 1228 | } |
| 1229 | |
| 1230 | /* Send NBD_OPT_ABORT as a courtesy before hanging up */ |
| 1231 | nbd_send_opt_abort(ioc); |
| 1232 | break; |
| 1233 | case NBD_MODE_EXPORT_NAME: |
| 1234 | error_setg(errp, "Server does not support export lists"); |
| 1235 | /* We can't even send NBD_OPT_ABORT, so merely hang up */ |
| 1236 | goto out; |
| 1237 | case NBD_MODE_OLDSTYLE: |
| 1238 | /* Lone export name is implied, but we can parse length and flags */ |
| 1239 | array = g_new0(NBDExportInfo, 1); |
| 1240 | array->name = g_strdup(""); |
| 1241 | array->mode = NBD_MODE_OLDSTYLE; |
| 1242 | count = 1; |
| 1243 | |
| 1244 | if (nbd_negotiate_finish_oldstyle(ioc, array, errp) < 0) { |
| 1245 | goto out; |
| 1246 | } |
| 1247 | |
| 1248 | /* Send NBD_CMD_DISC as a courtesy to the server, but ignore all |
| 1249 | * errors now that we have the information we wanted. */ |
| 1250 | if (nbd_drop(ioc, 124, NULL) == 0) { |
| 1251 | NBDRequest request = { .type = NBD_CMD_DISC, .mode = result }; |
| 1252 | |
| 1253 | nbd_send_request(ioc, &request); |
| 1254 | } |
| 1255 | break; |
| 1256 | default: |
| 1257 | g_assert_not_reached(); |
| 1258 | } |
| 1259 | |
| 1260 | *info = array; |
| 1261 | array = NULL; |
| 1262 | ret = count; |
| 1263 | |
| 1264 | out: |
| 1265 | qio_channel_shutdown(ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL); |
| 1266 | qio_channel_close(ioc, NULL); |
| 1267 | object_unref(OBJECT(sioc)); |
| 1268 | nbd_free_export_list(array, count); |
| 1269 | return ret; |
| 1270 | } |
| 1271 | |
| 1272 | #ifdef __linux__ |
| 1273 | int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info, |
| 1274 | Error **errp) |
| 1275 | { |
| 1276 | unsigned long sector_size = MAX(BDRV_SECTOR_SIZE, info->min_block); |
| 1277 | unsigned long sectors = info->size / sector_size; |
| 1278 | |
| 1279 | /* FIXME: Once the kernel module is patched to honor block sizes, |
| 1280 | * and to advertise that fact to user space, we should update the |
| 1281 | * hand-off to the kernel to use any block sizes we learned. */ |
| 1282 | assert(!info->request_sizes); |
| 1283 | if (info->size / sector_size != sectors) { |
| 1284 | error_setg(errp, "Export size %" PRIu64 " too large for 32-bit kernel", |
| 1285 | info->size); |
| 1286 | return -E2BIG; |
| 1287 | } |
| 1288 | |
| 1289 | trace_nbd_init_set_socket(); |
| 1290 | |
| 1291 | if (ioctl(fd, NBD_SET_SOCK, (unsigned long) sioc->fd) < 0) { |
| 1292 | int serrno = errno; |
| 1293 | error_setg(errp, "Failed to set NBD socket"); |
| 1294 | return -serrno; |
| 1295 | } |
| 1296 | |
| 1297 | trace_nbd_init_set_block_size(sector_size); |
| 1298 | |
| 1299 | if (ioctl(fd, NBD_SET_BLKSIZE, sector_size) < 0) { |
| 1300 | int serrno = errno; |
| 1301 | error_setg(errp, "Failed setting NBD block size"); |
| 1302 | return -serrno; |
| 1303 | } |
| 1304 | |
| 1305 | trace_nbd_init_set_size(sectors); |
| 1306 | if (info->size % sector_size) { |
| 1307 | trace_nbd_init_trailing_bytes(info->size % sector_size); |
| 1308 | } |
| 1309 | |
| 1310 | if (ioctl(fd, NBD_SET_SIZE_BLOCKS, sectors) < 0) { |
| 1311 | int serrno = errno; |
| 1312 | error_setg(errp, "Failed setting size (in blocks)"); |
| 1313 | return -serrno; |
| 1314 | } |
| 1315 | |
| 1316 | if (ioctl(fd, NBD_SET_FLAGS, (unsigned long) info->flags) < 0) { |
| 1317 | if (errno == ENOTTY) { |
| 1318 | int read_only = (info->flags & NBD_FLAG_READ_ONLY) != 0; |
| 1319 | trace_nbd_init_set_readonly(); |
| 1320 | |
| 1321 | if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) { |
| 1322 | int serrno = errno; |
| 1323 | error_setg(errp, "Failed setting read-only attribute"); |
| 1324 | return -serrno; |
| 1325 | } |
| 1326 | } else { |
| 1327 | int serrno = errno; |
| 1328 | error_setg(errp, "Failed setting flags"); |
| 1329 | return -serrno; |
| 1330 | } |
| 1331 | } |
| 1332 | |
| 1333 | trace_nbd_init_finish(); |
| 1334 | |
| 1335 | return 0; |
| 1336 | } |
| 1337 | |
| 1338 | int nbd_client(int fd) |
| 1339 | { |
| 1340 | int ret; |
| 1341 | int serrno; |
| 1342 | |
| 1343 | trace_nbd_client_loop(); |
| 1344 | |
| 1345 | ret = ioctl(fd, NBD_DO_IT); |
| 1346 | if (ret < 0 && errno == EPIPE) { |
| 1347 | /* NBD_DO_IT normally returns EPIPE when someone has disconnected |
| 1348 | * the socket via NBD_DISCONNECT. We do not want to return 1 in |
| 1349 | * that case. |
| 1350 | */ |
| 1351 | ret = 0; |
| 1352 | } |
| 1353 | serrno = errno; |
| 1354 | |
| 1355 | trace_nbd_client_loop_ret(ret, strerror(serrno)); |
| 1356 | |
| 1357 | trace_nbd_client_clear_queue(); |
| 1358 | ioctl(fd, NBD_CLEAR_QUE); |
| 1359 | |
| 1360 | trace_nbd_client_clear_socket(); |
| 1361 | ioctl(fd, NBD_CLEAR_SOCK); |
| 1362 | |
| 1363 | errno = serrno; |
| 1364 | return ret; |
| 1365 | } |
| 1366 | |
| 1367 | int nbd_disconnect(int fd) |
| 1368 | { |
| 1369 | ioctl(fd, NBD_CLEAR_QUE); |
| 1370 | ioctl(fd, NBD_DISCONNECT); |
| 1371 | ioctl(fd, NBD_CLEAR_SOCK); |
| 1372 | return 0; |
| 1373 | } |
| 1374 | |
| 1375 | #endif /* __linux__ */ |
| 1376 | |
| 1377 | int nbd_send_request(QIOChannel *ioc, NBDRequest *request) |
| 1378 | { |
| 1379 | uint8_t buf[NBD_EXTENDED_REQUEST_SIZE]; |
| 1380 | size_t len; |
| 1381 | |
| 1382 | trace_nbd_send_request(request->from, request->len, request->cookie, |
| 1383 | request->flags, request->type, |
| 1384 | nbd_cmd_lookup(request->type)); |
| 1385 | |
| 1386 | stw_be_p(buf + 4, request->flags); |
| 1387 | stw_be_p(buf + 6, request->type); |
| 1388 | stq_be_p(buf + 8, request->cookie); |
| 1389 | stq_be_p(buf + 16, request->from); |
| 1390 | if (request->mode >= NBD_MODE_EXTENDED) { |
| 1391 | stl_be_p(buf, NBD_EXTENDED_REQUEST_MAGIC); |
| 1392 | stq_be_p(buf + 24, request->len); |
| 1393 | len = NBD_EXTENDED_REQUEST_SIZE; |
| 1394 | } else { |
| 1395 | assert(request->len <= UINT32_MAX); |
| 1396 | stl_be_p(buf, NBD_REQUEST_MAGIC); |
| 1397 | stl_be_p(buf + 24, request->len); |
| 1398 | len = NBD_REQUEST_SIZE; |
| 1399 | } |
| 1400 | |
| 1401 | return nbd_write(ioc, buf, len, NULL); |
| 1402 | } |
| 1403 | |
| 1404 | /* nbd_receive_simple_reply |
| 1405 | * Read simple reply except magic field (which should be already read). |
| 1406 | * Payload is not read (payload is possible for CMD_READ, but here we even |
| 1407 | * don't know whether it take place or not). |
| 1408 | */ |
| 1409 | static int nbd_receive_simple_reply(QIOChannel *ioc, NBDSimpleReply *reply, |
| 1410 | Error **errp) |
| 1411 | { |
| 1412 | int ret; |
| 1413 | |
| 1414 | assert(reply->magic == NBD_SIMPLE_REPLY_MAGIC); |
| 1415 | |
| 1416 | ret = nbd_read(ioc, (uint8_t *)reply + sizeof(reply->magic), |
| 1417 | sizeof(*reply) - sizeof(reply->magic), "reply", errp); |
| 1418 | if (ret < 0) { |
| 1419 | return ret; |
| 1420 | } |
| 1421 | |
| 1422 | reply->error = be32_to_cpu(reply->error); |
| 1423 | reply->cookie = be64_to_cpu(reply->cookie); |
| 1424 | |
| 1425 | return 0; |
| 1426 | } |
| 1427 | |
| 1428 | /* nbd_receive_reply_chunk_header |
| 1429 | * Read structured reply chunk except magic field (which should be already |
| 1430 | * read). Normalize into the compact form. |
| 1431 | * Payload is not read. |
| 1432 | */ |
| 1433 | static int nbd_receive_reply_chunk_header(QIOChannel *ioc, NBDReply *chunk, |
| 1434 | Error **errp) |
| 1435 | { |
| 1436 | int ret; |
| 1437 | size_t len; |
| 1438 | uint64_t payload_len; |
| 1439 | |
| 1440 | if (chunk->magic == NBD_STRUCTURED_REPLY_MAGIC) { |
| 1441 | len = sizeof(chunk->structured); |
| 1442 | } else { |
| 1443 | assert(chunk->magic == NBD_EXTENDED_REPLY_MAGIC); |
| 1444 | len = sizeof(chunk->extended); |
| 1445 | } |
| 1446 | |
| 1447 | ret = nbd_read(ioc, (uint8_t *)chunk + sizeof(chunk->magic), |
| 1448 | len - sizeof(chunk->magic), "structured chunk", |
| 1449 | errp); |
| 1450 | if (ret < 0) { |
| 1451 | return ret; |
| 1452 | } |
| 1453 | |
| 1454 | /* flags, type, and cookie occupy same space between forms */ |
| 1455 | chunk->structured.flags = be16_to_cpu(chunk->structured.flags); |
| 1456 | chunk->structured.type = be16_to_cpu(chunk->structured.type); |
| 1457 | chunk->structured.cookie = be64_to_cpu(chunk->structured.cookie); |
| 1458 | |
| 1459 | /* |
| 1460 | * Because we use BLOCK_STATUS with REQ_ONE, and cap READ requests |
| 1461 | * at 32M, no valid server should send us payload larger than |
| 1462 | * this. Even if we stopped using REQ_ONE, sane servers will cap |
| 1463 | * the number of extents they return for block status. |
| 1464 | */ |
| 1465 | if (chunk->magic == NBD_STRUCTURED_REPLY_MAGIC) { |
| 1466 | payload_len = be32_to_cpu(chunk->structured.length); |
| 1467 | } else { |
| 1468 | /* For now, we are ignoring the extended header offset. */ |
| 1469 | payload_len = be64_to_cpu(chunk->extended.length); |
| 1470 | chunk->magic = NBD_STRUCTURED_REPLY_MAGIC; |
| 1471 | } |
| 1472 | if (payload_len > NBD_MAX_BUFFER_SIZE + sizeof(NBDStructuredReadData)) { |
| 1473 | error_setg(errp, "server chunk %" PRIu32 " (%s) payload is too long", |
| 1474 | chunk->structured.type, |
| 1475 | nbd_rep_lookup(chunk->structured.type)); |
| 1476 | return -EINVAL; |
| 1477 | } |
| 1478 | chunk->structured.length = payload_len; |
| 1479 | |
| 1480 | return 0; |
| 1481 | } |
| 1482 | |
| 1483 | /* nbd_read_eof |
| 1484 | * Tries to read @size bytes from @ioc. |
| 1485 | * Returns 1 on success |
| 1486 | * 0 on eof, when no data was read (errp is not set) |
| 1487 | * negative errno on failure (errp is set) |
| 1488 | */ |
| 1489 | static inline int coroutine_fn |
| 1490 | nbd_read_eof(BlockDriverState *bs, QIOChannel *ioc, void *buffer, size_t size, |
| 1491 | Error **errp) |
| 1492 | { |
| 1493 | bool partial = false; |
| 1494 | |
| 1495 | assert(size); |
| 1496 | while (size > 0) { |
| 1497 | struct iovec iov = { .iov_base = buffer, .iov_len = size }; |
| 1498 | ssize_t len; |
| 1499 | |
| 1500 | len = qio_channel_readv(ioc, &iov, 1, errp); |
| 1501 | if (len == QIO_CHANNEL_ERR_BLOCK) { |
| 1502 | qio_channel_yield(ioc, G_IO_IN); |
| 1503 | continue; |
| 1504 | } else if (len < 0) { |
| 1505 | return -EIO; |
| 1506 | } else if (len == 0) { |
| 1507 | if (partial) { |
| 1508 | error_setg(errp, |
| 1509 | "Unexpected end-of-file before all bytes were read"); |
| 1510 | return -EIO; |
| 1511 | } else { |
| 1512 | return 0; |
| 1513 | } |
| 1514 | } |
| 1515 | |
| 1516 | partial = true; |
| 1517 | size -= len; |
| 1518 | buffer = (uint8_t*) buffer + len; |
| 1519 | } |
| 1520 | return 1; |
| 1521 | } |
| 1522 | |
| 1523 | /* nbd_receive_reply |
| 1524 | * |
| 1525 | * Wait for a new reply. If this yields, the coroutine must be able to be |
| 1526 | * safely reentered for nbd_client_attach_aio_context(). @mode determines |
| 1527 | * which reply magic we are expecting, although this normalizes the result |
| 1528 | * so that the caller only has to work with compact headers. |
| 1529 | * |
| 1530 | * Returns 1 on success |
| 1531 | * 0 on eof, when no data was read |
| 1532 | * negative errno on failure |
| 1533 | */ |
| 1534 | int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc, |
| 1535 | NBDReply *reply, NBDMode mode, Error **errp) |
| 1536 | { |
| 1537 | int ret; |
| 1538 | const char *type; |
| 1539 | uint32_t expected; |
| 1540 | |
| 1541 | ret = nbd_read_eof(bs, ioc, &reply->magic, sizeof(reply->magic), errp); |
| 1542 | if (ret <= 0) { |
| 1543 | return ret; |
| 1544 | } |
| 1545 | |
| 1546 | reply->magic = be32_to_cpu(reply->magic); |
| 1547 | |
| 1548 | /* Diagnose but accept wrong-width header */ |
| 1549 | switch (reply->magic) { |
| 1550 | case NBD_SIMPLE_REPLY_MAGIC: |
| 1551 | if (mode >= NBD_MODE_EXTENDED) { |
| 1552 | trace_nbd_receive_wrong_header(reply->magic, |
| 1553 | nbd_mode_lookup(mode)); |
| 1554 | } |
| 1555 | ret = nbd_receive_simple_reply(ioc, &reply->simple, errp); |
| 1556 | if (ret < 0) { |
| 1557 | return ret; |
| 1558 | } |
| 1559 | trace_nbd_receive_simple_reply(reply->simple.error, |
| 1560 | nbd_err_lookup(reply->simple.error), |
| 1561 | reply->cookie); |
| 1562 | break; |
| 1563 | case NBD_STRUCTURED_REPLY_MAGIC: |
| 1564 | case NBD_EXTENDED_REPLY_MAGIC: |
| 1565 | expected = mode >= NBD_MODE_EXTENDED ? NBD_EXTENDED_REPLY_MAGIC |
| 1566 | : NBD_STRUCTURED_REPLY_MAGIC; |
| 1567 | if (reply->magic != expected) { |
| 1568 | trace_nbd_receive_wrong_header(reply->magic, |
| 1569 | nbd_mode_lookup(mode)); |
| 1570 | } |
| 1571 | ret = nbd_receive_reply_chunk_header(ioc, reply, errp); |
| 1572 | if (ret < 0) { |
| 1573 | return ret; |
| 1574 | } |
| 1575 | type = nbd_reply_type_lookup(reply->structured.type); |
| 1576 | trace_nbd_receive_reply_chunk_header(reply->structured.flags, |
| 1577 | reply->structured.type, type, |
| 1578 | reply->structured.cookie, |
| 1579 | reply->structured.length); |
| 1580 | break; |
| 1581 | default: |
| 1582 | trace_nbd_receive_wrong_header(reply->magic, nbd_mode_lookup(mode)); |
| 1583 | error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", reply->magic); |
| 1584 | return -EINVAL; |
| 1585 | } |
| 1586 | |
| 1587 | return 1; |
| 1588 | } |
| 1589 |