| /* |
| * Copyright (C) 2016-2017 Red Hat, Inc. |
| * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws> |
| * |
| * Network Block Device Client Side |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; under version 2 of the License. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "qapi/error.h" |
| #include "trace.h" |
| #include "nbd-internal.h" |
| |
| static int nbd_errno_to_system_errno(int err) |
| { |
| int ret; |
| switch (err) { |
| case NBD_SUCCESS: |
| ret = 0; |
| break; |
| case NBD_EPERM: |
| ret = EPERM; |
| break; |
| case NBD_EIO: |
| ret = EIO; |
| break; |
| case NBD_ENOMEM: |
| ret = ENOMEM; |
| break; |
| case NBD_ENOSPC: |
| ret = ENOSPC; |
| break; |
| case NBD_ESHUTDOWN: |
| ret = ESHUTDOWN; |
| break; |
| default: |
| trace_nbd_unknown_error(err); |
| /* fallthrough */ |
| case NBD_EINVAL: |
| ret = EINVAL; |
| break; |
| } |
| return ret; |
| } |
| |
| /* Definitions for opaque data types */ |
| |
| static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); |
| |
| /* That's all folks */ |
| |
| /* Basic flow for negotiation |
| |
| Server Client |
| Negotiate |
| |
| or |
| |
| Server Client |
| Negotiate #1 |
| Option |
| Negotiate #2 |
| |
| ---- |
| |
| followed by |
| |
| Server Client |
| Request |
| Response |
| Request |
| Response |
| ... |
| ... |
| Request (type == 2) |
| |
| */ |
| |
| /* Send an option request. |
| * |
| * The request is for option @opt, with @data containing @len bytes of |
| * additional payload for the request (@len may be -1 to treat @data as |
| * a C string; and @data may be NULL if @len is 0). |
| * Return 0 if successful, -1 with errp set if it is impossible to |
| * continue. */ |
| static int nbd_send_option_request(QIOChannel *ioc, uint32_t opt, |
| uint32_t len, const char *data, |
| Error **errp) |
| { |
| nbd_option req; |
| QEMU_BUILD_BUG_ON(sizeof(req) != 16); |
| |
| if (len == -1) { |
| req.length = len = strlen(data); |
| } |
| trace_nbd_send_option_request(opt, nbd_opt_lookup(opt), len); |
| |
| stq_be_p(&req.magic, NBD_OPTS_MAGIC); |
| stl_be_p(&req.option, opt); |
| stl_be_p(&req.length, len); |
| |
| if (nbd_write(ioc, &req, sizeof(req), errp) < 0) { |
| error_prepend(errp, "Failed to send option request header"); |
| return -1; |
| } |
| |
| if (len && nbd_write(ioc, (char *) data, len, errp) < 0) { |
| error_prepend(errp, "Failed to send option request data"); |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| /* Send NBD_OPT_ABORT as a courtesy to let the server know that we are |
| * not going to attempt further negotiation. */ |
| static void nbd_send_opt_abort(QIOChannel *ioc) |
| { |
| /* Technically, a compliant server is supposed to reply to us; but |
| * older servers disconnected instead. At any rate, we're allowed |
| * to disconnect without waiting for the server reply, so we don't |
| * even care if the request makes it to the server, let alone |
| * waiting around for whether the server replies. */ |
| nbd_send_option_request(ioc, NBD_OPT_ABORT, 0, NULL, NULL); |
| } |
| |
| |
| /* Receive the header of an option reply, which should match the given |
| * opt. Read through the length field, but NOT the length bytes of |
| * payload. Return 0 if successful, -1 with errp set if it is |
| * impossible to continue. */ |
| static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt, |
| nbd_opt_reply *reply, Error **errp) |
| { |
| QEMU_BUILD_BUG_ON(sizeof(*reply) != 20); |
| if (nbd_read(ioc, reply, sizeof(*reply), errp) < 0) { |
| error_prepend(errp, "failed to read option reply"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| be64_to_cpus(&reply->magic); |
| be32_to_cpus(&reply->option); |
| be32_to_cpus(&reply->type); |
| be32_to_cpus(&reply->length); |
| |
| trace_nbd_receive_option_reply(reply->option, nbd_opt_lookup(reply->option), |
| reply->type, nbd_rep_lookup(reply->type), |
| reply->length); |
| |
| if (reply->magic != NBD_REP_MAGIC) { |
| error_setg(errp, "Unexpected option reply magic"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (reply->option != opt) { |
| error_setg(errp, "Unexpected option type %x expected %x", |
| reply->option, opt); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| return 0; |
| } |
| |
| /* If reply represents success, return 1 without further action. |
| * If reply represents an error, consume the optional payload of |
| * the packet on ioc. Then return 0 for unsupported (so the client |
| * can fall back to other approaches), or -1 with errp set for other |
| * errors. |
| */ |
| static int nbd_handle_reply_err(QIOChannel *ioc, nbd_opt_reply *reply, |
| Error **errp) |
| { |
| char *msg = NULL; |
| int result = -1; |
| |
| if (!(reply->type & (1 << 31))) { |
| return 1; |
| } |
| |
| if (reply->length) { |
| if (reply->length > NBD_MAX_BUFFER_SIZE) { |
| error_setg(errp, "server error 0x%" PRIx32 |
| " (%s) message is too long", |
| reply->type, nbd_rep_lookup(reply->type)); |
| goto cleanup; |
| } |
| msg = g_malloc(reply->length + 1); |
| if (nbd_read(ioc, msg, reply->length, errp) < 0) { |
| error_prepend(errp, "failed to read option error 0x%" PRIx32 |
| " (%s) message", |
| reply->type, nbd_rep_lookup(reply->type)); |
| goto cleanup; |
| } |
| msg[reply->length] = '\0'; |
| } |
| |
| switch (reply->type) { |
| case NBD_REP_ERR_UNSUP: |
| trace_nbd_reply_err_unsup(reply->option, nbd_opt_lookup(reply->option)); |
| result = 0; |
| goto cleanup; |
| |
| case NBD_REP_ERR_POLICY: |
| error_setg(errp, "Denied by server for option %" PRIx32 " (%s)", |
| reply->option, nbd_opt_lookup(reply->option)); |
| break; |
| |
| case NBD_REP_ERR_INVALID: |
| error_setg(errp, "Invalid data length for option %" PRIx32 " (%s)", |
| reply->option, nbd_opt_lookup(reply->option)); |
| break; |
| |
| case NBD_REP_ERR_PLATFORM: |
| error_setg(errp, "Server lacks support for option %" PRIx32 " (%s)", |
| reply->option, nbd_opt_lookup(reply->option)); |
| break; |
| |
| case NBD_REP_ERR_TLS_REQD: |
| error_setg(errp, "TLS negotiation required before option %" PRIx32 |
| " (%s)", reply->option, nbd_opt_lookup(reply->option)); |
| break; |
| |
| case NBD_REP_ERR_UNKNOWN: |
| error_setg(errp, "Requested export not available"); |
| break; |
| |
| case NBD_REP_ERR_SHUTDOWN: |
| error_setg(errp, "Server shutting down before option %" PRIx32 " (%s)", |
| reply->option, nbd_opt_lookup(reply->option)); |
| break; |
| |
| case NBD_REP_ERR_BLOCK_SIZE_REQD: |
| error_setg(errp, "Server requires INFO_BLOCK_SIZE for option %" PRIx32 |
| " (%s)", reply->option, nbd_opt_lookup(reply->option)); |
| break; |
| |
| default: |
| error_setg(errp, "Unknown error code when asking for option %" PRIx32 |
| " (%s)", reply->option, nbd_opt_lookup(reply->option)); |
| break; |
| } |
| |
| if (msg) { |
| error_append_hint(errp, "server reported: %s\n", msg); |
| } |
| |
| cleanup: |
| g_free(msg); |
| if (result < 0) { |
| nbd_send_opt_abort(ioc); |
| } |
| return result; |
| } |
| |
| /* Process another portion of the NBD_OPT_LIST reply. Set *@match if |
| * the current reply matches @want or if the server does not support |
| * NBD_OPT_LIST, otherwise leave @match alone. Return 0 if iteration |
| * is complete, positive if more replies are expected, or negative |
| * with @errp set if an unrecoverable error occurred. */ |
| static int nbd_receive_list(QIOChannel *ioc, const char *want, bool *match, |
| Error **errp) |
| { |
| nbd_opt_reply reply; |
| uint32_t len; |
| uint32_t namelen; |
| char name[NBD_MAX_NAME_SIZE + 1]; |
| int error; |
| |
| if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) { |
| return -1; |
| } |
| error = nbd_handle_reply_err(ioc, &reply, errp); |
| if (error <= 0) { |
| /* The server did not support NBD_OPT_LIST, so set *match on |
| * the assumption that any name will be accepted. */ |
| *match = true; |
| return error; |
| } |
| len = reply.length; |
| |
| if (reply.type == NBD_REP_ACK) { |
| if (len != 0) { |
| error_setg(errp, "length too long for option end"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| return 0; |
| } else if (reply.type != NBD_REP_SERVER) { |
| error_setg(errp, "Unexpected reply type %" PRIx32 " expected %x", |
| reply.type, NBD_REP_SERVER); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| |
| if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) { |
| error_setg(errp, "incorrect option length %" PRIu32, len); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (nbd_read(ioc, &namelen, sizeof(namelen), errp) < 0) { |
| error_prepend(errp, "failed to read option name length"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| namelen = be32_to_cpu(namelen); |
| len -= sizeof(namelen); |
| if (len < namelen) { |
| error_setg(errp, "incorrect option name length"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (namelen != strlen(want)) { |
| if (nbd_drop(ioc, len, errp) < 0) { |
| error_prepend(errp, "failed to skip export name with wrong length"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| return 1; |
| } |
| |
| assert(namelen < sizeof(name)); |
| if (nbd_read(ioc, name, namelen, errp) < 0) { |
| error_prepend(errp, "failed to read export name"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| name[namelen] = '\0'; |
| len -= namelen; |
| if (nbd_drop(ioc, len, errp) < 0) { |
| error_prepend(errp, "failed to read export description"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (!strcmp(name, want)) { |
| *match = true; |
| } |
| return 1; |
| } |
| |
| |
| /* Returns -1 if NBD_OPT_GO proves the export @wantname cannot be |
| * used, 0 if NBD_OPT_GO is unsupported (fall back to NBD_OPT_LIST and |
| * NBD_OPT_EXPORT_NAME in that case), and > 0 if the export is good to |
| * go (with @info populated). */ |
| static int nbd_opt_go(QIOChannel *ioc, const char *wantname, |
| NBDExportInfo *info, Error **errp) |
| { |
| nbd_opt_reply reply; |
| uint32_t len = strlen(wantname); |
| uint16_t type; |
| int error; |
| char *buf; |
| |
| /* The protocol requires that the server send NBD_INFO_EXPORT with |
| * a non-zero flags (at least NBD_FLAG_HAS_FLAGS must be set); so |
| * flags still 0 is a witness of a broken server. */ |
| info->flags = 0; |
| |
| trace_nbd_opt_go_start(wantname); |
| buf = g_malloc(4 + len + 2 + 2 * info->request_sizes + 1); |
| stl_be_p(buf, len); |
| memcpy(buf + 4, wantname, len); |
| /* At most one request, everything else up to server */ |
| stw_be_p(buf + 4 + len, info->request_sizes); |
| if (info->request_sizes) { |
| stw_be_p(buf + 4 + len + 2, NBD_INFO_BLOCK_SIZE); |
| } |
| error = nbd_send_option_request(ioc, NBD_OPT_GO, |
| 4 + len + 2 + 2 * info->request_sizes, |
| buf, errp); |
| g_free(buf); |
| if (error < 0) { |
| return -1; |
| } |
| |
| while (1) { |
| if (nbd_receive_option_reply(ioc, NBD_OPT_GO, &reply, errp) < 0) { |
| return -1; |
| } |
| error = nbd_handle_reply_err(ioc, &reply, errp); |
| if (error <= 0) { |
| return error; |
| } |
| len = reply.length; |
| |
| if (reply.type == NBD_REP_ACK) { |
| /* Server is done sending info and moved into transmission |
| phase, but make sure it sent flags */ |
| if (len) { |
| error_setg(errp, "server sent invalid NBD_REP_ACK"); |
| return -1; |
| } |
| if (!info->flags) { |
| error_setg(errp, "broken server omitted NBD_INFO_EXPORT"); |
| return -1; |
| } |
| trace_nbd_opt_go_success(); |
| return 1; |
| } |
| if (reply.type != NBD_REP_INFO) { |
| error_setg(errp, "unexpected reply type %" PRIx32 |
| " (%s), expected %x", |
| reply.type, nbd_rep_lookup(reply.type), NBD_REP_INFO); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (len < sizeof(type)) { |
| error_setg(errp, "NBD_REP_INFO length %" PRIu32 " is too short", |
| len); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (nbd_read(ioc, &type, sizeof(type), errp) < 0) { |
| error_prepend(errp, "failed to read info type"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| len -= sizeof(type); |
| be16_to_cpus(&type); |
| switch (type) { |
| case NBD_INFO_EXPORT: |
| if (len != sizeof(info->size) + sizeof(info->flags)) { |
| error_setg(errp, "remaining export info len %" PRIu32 |
| " is unexpected size", len); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) { |
| error_prepend(errp, "failed to read info size"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| be64_to_cpus(&info->size); |
| if (nbd_read(ioc, &info->flags, sizeof(info->flags), errp) < 0) { |
| error_prepend(errp, "failed to read info flags"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| be16_to_cpus(&info->flags); |
| trace_nbd_receive_negotiate_size_flags(info->size, info->flags); |
| break; |
| |
| case NBD_INFO_BLOCK_SIZE: |
| if (len != sizeof(info->min_block) * 3) { |
| error_setg(errp, "remaining export info len %" PRIu32 |
| " is unexpected size", len); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (nbd_read(ioc, &info->min_block, sizeof(info->min_block), |
| errp) < 0) { |
| error_prepend(errp, "failed to read info minimum block size"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| be32_to_cpus(&info->min_block); |
| if (!is_power_of_2(info->min_block)) { |
| error_setg(errp, "server minimum block size %" PRId32 |
| "is not a power of two", info->min_block); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (nbd_read(ioc, &info->opt_block, sizeof(info->opt_block), |
| errp) < 0) { |
| error_prepend(errp, "failed to read info preferred block size"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| be32_to_cpus(&info->opt_block); |
| if (!is_power_of_2(info->opt_block) || |
| info->opt_block < info->min_block) { |
| error_setg(errp, "server preferred block size %" PRId32 |
| "is not valid", info->opt_block); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| if (nbd_read(ioc, &info->max_block, sizeof(info->max_block), |
| errp) < 0) { |
| error_prepend(errp, "failed to read info maximum block size"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| be32_to_cpus(&info->max_block); |
| trace_nbd_opt_go_info_block_size(info->min_block, info->opt_block, |
| info->max_block); |
| break; |
| |
| default: |
| trace_nbd_opt_go_info_unknown(type, nbd_info_lookup(type)); |
| if (nbd_drop(ioc, len, errp) < 0) { |
| error_prepend(errp, "Failed to read info payload"); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| break; |
| } |
| } |
| } |
| |
| /* Return -1 on failure, 0 if wantname is an available export. */ |
| static int nbd_receive_query_exports(QIOChannel *ioc, |
| const char *wantname, |
| Error **errp) |
| { |
| bool foundExport = false; |
| |
| trace_nbd_receive_query_exports_start(wantname); |
| if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) { |
| return -1; |
| } |
| |
| while (1) { |
| int ret = nbd_receive_list(ioc, wantname, &foundExport, errp); |
| |
| if (ret < 0) { |
| /* Server gave unexpected reply */ |
| return -1; |
| } else if (ret == 0) { |
| /* Done iterating. */ |
| if (!foundExport) { |
| error_setg(errp, "No export with name '%s' available", |
| wantname); |
| nbd_send_opt_abort(ioc); |
| return -1; |
| } |
| trace_nbd_receive_query_exports_success(wantname); |
| return 0; |
| } |
| } |
| } |
| |
| static QIOChannel *nbd_receive_starttls(QIOChannel *ioc, |
| QCryptoTLSCreds *tlscreds, |
| const char *hostname, Error **errp) |
| { |
| nbd_opt_reply reply; |
| QIOChannelTLS *tioc; |
| struct NBDTLSHandshakeData data = { 0 }; |
| |
| trace_nbd_receive_starttls_request(); |
| if (nbd_send_option_request(ioc, NBD_OPT_STARTTLS, 0, NULL, errp) < 0) { |
| return NULL; |
| } |
| |
| trace_nbd_receive_starttls_reply(); |
| if (nbd_receive_option_reply(ioc, NBD_OPT_STARTTLS, &reply, errp) < 0) { |
| return NULL; |
| } |
| |
| if (reply.type != NBD_REP_ACK) { |
| error_setg(errp, "Server rejected request to start TLS %" PRIx32, |
| reply.type); |
| nbd_send_opt_abort(ioc); |
| return NULL; |
| } |
| |
| if (reply.length != 0) { |
| error_setg(errp, "Start TLS response was not zero %" PRIu32, |
| reply.length); |
| nbd_send_opt_abort(ioc); |
| return NULL; |
| } |
| |
| trace_nbd_receive_starttls_new_client(); |
| tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp); |
| if (!tioc) { |
| return NULL; |
| } |
| qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-client-tls"); |
| data.loop = g_main_loop_new(g_main_context_default(), FALSE); |
| trace_nbd_receive_starttls_tls_handshake(); |
| qio_channel_tls_handshake(tioc, |
| nbd_tls_handshake, |
| &data, |
| NULL); |
| |
| if (!data.complete) { |
| g_main_loop_run(data.loop); |
| } |
| g_main_loop_unref(data.loop); |
| if (data.error) { |
| error_propagate(errp, data.error); |
| object_unref(OBJECT(tioc)); |
| return NULL; |
| } |
| |
| return QIO_CHANNEL(tioc); |
| } |
| |
| |
| int nbd_receive_negotiate(QIOChannel *ioc, const char *name, |
| QCryptoTLSCreds *tlscreds, const char *hostname, |
| QIOChannel **outioc, NBDExportInfo *info, |
| Error **errp) |
| { |
| char buf[256]; |
| uint64_t magic; |
| int rc; |
| bool zeroes = true; |
| |
| trace_nbd_receive_negotiate(tlscreds, hostname ? hostname : "<null>"); |
| |
| rc = -EINVAL; |
| |
| if (outioc) { |
| *outioc = NULL; |
| } |
| if (tlscreds && !outioc) { |
| error_setg(errp, "Output I/O channel required for TLS"); |
| goto fail; |
| } |
| |
| if (nbd_read(ioc, buf, 8, errp) < 0) { |
| error_prepend(errp, "Failed to read data"); |
| goto fail; |
| } |
| |
| buf[8] = '\0'; |
| if (strlen(buf) == 0) { |
| error_setg(errp, "Server connection closed unexpectedly"); |
| goto fail; |
| } |
| |
| magic = ldq_be_p(buf); |
| trace_nbd_receive_negotiate_magic(magic); |
| |
| if (memcmp(buf, "NBDMAGIC", 8) != 0) { |
| error_setg(errp, "Invalid magic received"); |
| goto fail; |
| } |
| |
| if (nbd_read(ioc, &magic, sizeof(magic), errp) < 0) { |
| error_prepend(errp, "Failed to read magic"); |
| goto fail; |
| } |
| magic = be64_to_cpu(magic); |
| trace_nbd_receive_negotiate_magic(magic); |
| |
| if (magic == NBD_OPTS_MAGIC) { |
| uint32_t clientflags = 0; |
| uint16_t globalflags; |
| bool fixedNewStyle = false; |
| |
| if (nbd_read(ioc, &globalflags, sizeof(globalflags), errp) < 0) { |
| error_prepend(errp, "Failed to read server flags"); |
| goto fail; |
| } |
| globalflags = be16_to_cpu(globalflags); |
| trace_nbd_receive_negotiate_server_flags(globalflags); |
| if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) { |
| fixedNewStyle = true; |
| clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE; |
| } |
| if (globalflags & NBD_FLAG_NO_ZEROES) { |
| zeroes = false; |
| clientflags |= NBD_FLAG_C_NO_ZEROES; |
| } |
| /* client requested flags */ |
| clientflags = cpu_to_be32(clientflags); |
| if (nbd_write(ioc, &clientflags, sizeof(clientflags), errp) < 0) { |
| error_prepend(errp, "Failed to send clientflags field"); |
| goto fail; |
| } |
| if (tlscreds) { |
| if (fixedNewStyle) { |
| *outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp); |
| if (!*outioc) { |
| goto fail; |
| } |
| ioc = *outioc; |
| } else { |
| error_setg(errp, "Server does not support STARTTLS"); |
| goto fail; |
| } |
| } |
| if (!name) { |
| trace_nbd_receive_negotiate_default_name(); |
| name = ""; |
| } |
| if (fixedNewStyle) { |
| int result; |
| |
| /* Try NBD_OPT_GO first - if it works, we are done (it |
| * also gives us a good message if the server requires |
| * TLS). If it is not available, fall back to |
| * NBD_OPT_LIST for nicer error messages about a missing |
| * export, then use NBD_OPT_EXPORT_NAME. */ |
| result = nbd_opt_go(ioc, name, info, errp); |
| if (result < 0) { |
| goto fail; |
| } |
| if (result > 0) { |
| return 0; |
| } |
| /* Check our desired export is present in the |
| * server export list. Since NBD_OPT_EXPORT_NAME |
| * cannot return an error message, running this |
| * query gives us better error reporting if the |
| * export name is not available. |
| */ |
| if (nbd_receive_query_exports(ioc, name, errp) < 0) { |
| goto fail; |
| } |
| } |
| /* write the export name request */ |
| if (nbd_send_option_request(ioc, NBD_OPT_EXPORT_NAME, -1, name, |
| errp) < 0) { |
| goto fail; |
| } |
| |
| /* Read the response */ |
| if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) { |
| error_prepend(errp, "Failed to read export length"); |
| goto fail; |
| } |
| be64_to_cpus(&info->size); |
| |
| if (nbd_read(ioc, &info->flags, sizeof(info->flags), errp) < 0) { |
| error_prepend(errp, "Failed to read export flags"); |
| goto fail; |
| } |
| be16_to_cpus(&info->flags); |
| } else if (magic == NBD_CLIENT_MAGIC) { |
| uint32_t oldflags; |
| |
| if (name) { |
| error_setg(errp, "Server does not support export names"); |
| goto fail; |
| } |
| if (tlscreds) { |
| error_setg(errp, "Server does not support STARTTLS"); |
| goto fail; |
| } |
| |
| if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) { |
| error_prepend(errp, "Failed to read export length"); |
| goto fail; |
| } |
| be64_to_cpus(&info->size); |
| |
| if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) { |
| error_prepend(errp, "Failed to read export flags"); |
| goto fail; |
| } |
| be32_to_cpus(&oldflags); |
| if (oldflags & ~0xffff) { |
| error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags); |
| goto fail; |
| } |
| info->flags = oldflags; |
| } else { |
| error_setg(errp, "Bad magic received"); |
| goto fail; |
| } |
| |
| trace_nbd_receive_negotiate_size_flags(info->size, info->flags); |
| if (zeroes && nbd_drop(ioc, 124, errp) < 0) { |
| error_prepend(errp, "Failed to read reserved block"); |
| goto fail; |
| } |
| rc = 0; |
| |
| fail: |
| return rc; |
| } |
| |
| #ifdef __linux__ |
| int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info, |
| Error **errp) |
| { |
| unsigned long sector_size = MAX(BDRV_SECTOR_SIZE, info->min_block); |
| unsigned long sectors = info->size / sector_size; |
| |
| /* FIXME: Once the kernel module is patched to honor block sizes, |
| * and to advertise that fact to user space, we should update the |
| * hand-off to the kernel to use any block sizes we learned. */ |
| assert(!info->request_sizes); |
| if (info->size / sector_size != sectors) { |
| error_setg(errp, "Export size %" PRIu64 " too large for 32-bit kernel", |
| info->size); |
| return -E2BIG; |
| } |
| |
| trace_nbd_init_set_socket(); |
| |
| if (ioctl(fd, NBD_SET_SOCK, (unsigned long) sioc->fd) < 0) { |
| int serrno = errno; |
| error_setg(errp, "Failed to set NBD socket"); |
| return -serrno; |
| } |
| |
| trace_nbd_init_set_block_size(sector_size); |
| |
| if (ioctl(fd, NBD_SET_BLKSIZE, sector_size) < 0) { |
| int serrno = errno; |
| error_setg(errp, "Failed setting NBD block size"); |
| return -serrno; |
| } |
| |
| trace_nbd_init_set_size(sectors); |
| if (info->size % sector_size) { |
| trace_nbd_init_trailing_bytes(info->size % sector_size); |
| } |
| |
| if (ioctl(fd, NBD_SET_SIZE_BLOCKS, sectors) < 0) { |
| int serrno = errno; |
| error_setg(errp, "Failed setting size (in blocks)"); |
| return -serrno; |
| } |
| |
| if (ioctl(fd, NBD_SET_FLAGS, (unsigned long) info->flags) < 0) { |
| if (errno == ENOTTY) { |
| int read_only = (info->flags & NBD_FLAG_READ_ONLY) != 0; |
| trace_nbd_init_set_readonly(); |
| |
| if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) { |
| int serrno = errno; |
| error_setg(errp, "Failed setting read-only attribute"); |
| return -serrno; |
| } |
| } else { |
| int serrno = errno; |
| error_setg(errp, "Failed setting flags"); |
| return -serrno; |
| } |
| } |
| |
| trace_nbd_init_finish(); |
| |
| return 0; |
| } |
| |
| int nbd_client(int fd) |
| { |
| int ret; |
| int serrno; |
| |
| trace_nbd_client_loop(); |
| |
| ret = ioctl(fd, NBD_DO_IT); |
| if (ret < 0 && errno == EPIPE) { |
| /* NBD_DO_IT normally returns EPIPE when someone has disconnected |
| * the socket via NBD_DISCONNECT. We do not want to return 1 in |
| * that case. |
| */ |
| ret = 0; |
| } |
| serrno = errno; |
| |
| trace_nbd_client_loop_ret(ret, strerror(serrno)); |
| |
| trace_nbd_client_clear_queue(); |
| ioctl(fd, NBD_CLEAR_QUE); |
| |
| trace_nbd_client_clear_socket(); |
| ioctl(fd, NBD_CLEAR_SOCK); |
| |
| errno = serrno; |
| return ret; |
| } |
| |
| int nbd_disconnect(int fd) |
| { |
| ioctl(fd, NBD_CLEAR_QUE); |
| ioctl(fd, NBD_DISCONNECT); |
| ioctl(fd, NBD_CLEAR_SOCK); |
| return 0; |
| } |
| |
| #else |
| int nbd_init(int fd, QIOChannelSocket *ioc, NBDExportInfo *info, |
| Error **errp) |
| { |
| error_setg(errp, "nbd_init is only supported on Linux"); |
| return -ENOTSUP; |
| } |
| |
| int nbd_client(int fd) |
| { |
| return -ENOTSUP; |
| } |
| int nbd_disconnect(int fd) |
| { |
| return -ENOTSUP; |
| } |
| #endif |
| |
| int nbd_send_request(QIOChannel *ioc, NBDRequest *request) |
| { |
| uint8_t buf[NBD_REQUEST_SIZE]; |
| |
| trace_nbd_send_request(request->from, request->len, request->handle, |
| request->flags, request->type, |
| nbd_cmd_lookup(request->type)); |
| |
| stl_be_p(buf, NBD_REQUEST_MAGIC); |
| stw_be_p(buf + 4, request->flags); |
| stw_be_p(buf + 6, request->type); |
| stq_be_p(buf + 8, request->handle); |
| stq_be_p(buf + 16, request->from); |
| stl_be_p(buf + 24, request->len); |
| |
| return nbd_write(ioc, buf, sizeof(buf), NULL); |
| } |
| |
| /* nbd_receive_reply |
| * Returns 1 on success |
| * 0 on eof, when no data was read (errp is not set) |
| * negative errno on failure (errp is set) |
| */ |
| int nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp) |
| { |
| uint8_t buf[NBD_REPLY_SIZE]; |
| uint32_t magic; |
| int ret; |
| |
| ret = nbd_read_eof(ioc, buf, sizeof(buf), errp); |
| if (ret <= 0) { |
| return ret; |
| } |
| |
| /* Reply |
| [ 0 .. 3] magic (NBD_REPLY_MAGIC) |
| [ 4 .. 7] error (0 == no error) |
| [ 7 .. 15] handle |
| */ |
| |
| magic = ldl_be_p(buf); |
| reply->error = ldl_be_p(buf + 4); |
| reply->handle = ldq_be_p(buf + 8); |
| |
| reply->error = nbd_errno_to_system_errno(reply->error); |
| |
| if (reply->error == ESHUTDOWN) { |
| /* This works even on mingw which lacks a native ESHUTDOWN */ |
| error_setg(errp, "server shutting down"); |
| return -EINVAL; |
| } |
| trace_nbd_receive_reply(magic, reply->error, reply->handle); |
| |
| if (magic != NBD_REPLY_MAGIC) { |
| error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); |
| return -EINVAL; |
| } |
| |
| return 1; |
| } |
| |
