| /* |
| * Copyright (C) 2016 Red Hat, Inc. |
| * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws> |
| * |
| * Network Block Device Server 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 "nbd-internal.h" |
| |
| static int system_errno_to_nbd_errno(int err) |
| { |
| switch (err) { |
| case 0: |
| return NBD_SUCCESS; |
| case EPERM: |
| case EROFS: |
| return NBD_EPERM; |
| case EIO: |
| return NBD_EIO; |
| case ENOMEM: |
| return NBD_ENOMEM; |
| #ifdef EDQUOT |
| case EDQUOT: |
| #endif |
| case EFBIG: |
| case ENOSPC: |
| return NBD_ENOSPC; |
| case ESHUTDOWN: |
| return NBD_ESHUTDOWN; |
| case EINVAL: |
| default: |
| return NBD_EINVAL; |
| } |
| } |
| |
| /* Definitions for opaque data types */ |
| |
| typedef struct NBDRequestData NBDRequestData; |
| |
| struct NBDRequestData { |
| QSIMPLEQ_ENTRY(NBDRequestData) entry; |
| NBDClient *client; |
| uint8_t *data; |
| bool complete; |
| }; |
| |
| struct NBDExport { |
| int refcount; |
| void (*close)(NBDExport *exp); |
| |
| BlockBackend *blk; |
| char *name; |
| char *description; |
| off_t dev_offset; |
| off_t size; |
| uint16_t nbdflags; |
| QTAILQ_HEAD(, NBDClient) clients; |
| QTAILQ_ENTRY(NBDExport) next; |
| |
| AioContext *ctx; |
| |
| BlockBackend *eject_notifier_blk; |
| Notifier eject_notifier; |
| }; |
| |
| static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); |
| |
| struct NBDClient { |
| int refcount; |
| void (*close)(NBDClient *client); |
| |
| bool no_zeroes; |
| NBDExport *exp; |
| QCryptoTLSCreds *tlscreds; |
| char *tlsaclname; |
| QIOChannelSocket *sioc; /* The underlying data channel */ |
| QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ |
| |
| Coroutine *recv_coroutine; |
| |
| CoMutex send_lock; |
| Coroutine *send_coroutine; |
| |
| QTAILQ_ENTRY(NBDClient) next; |
| int nb_requests; |
| bool closing; |
| }; |
| |
| /* That's all folks */ |
| |
| static void nbd_client_receive_next_request(NBDClient *client); |
| |
| static gboolean nbd_negotiate_continue(QIOChannel *ioc, |
| GIOCondition condition, |
| void *opaque) |
| { |
| qemu_coroutine_enter(opaque); |
| return TRUE; |
| } |
| |
| static ssize_t nbd_negotiate_read(QIOChannel *ioc, void *buffer, size_t size) |
| { |
| ssize_t ret; |
| guint watch; |
| |
| assert(qemu_in_coroutine()); |
| /* Negotiation are always in main loop. */ |
| watch = qio_channel_add_watch(ioc, |
| G_IO_IN, |
| nbd_negotiate_continue, |
| qemu_coroutine_self(), |
| NULL); |
| ret = read_sync(ioc, buffer, size); |
| g_source_remove(watch); |
| return ret; |
| |
| } |
| |
| static ssize_t nbd_negotiate_write(QIOChannel *ioc, const void *buffer, |
| size_t size) |
| { |
| ssize_t ret; |
| guint watch; |
| |
| assert(qemu_in_coroutine()); |
| /* Negotiation are always in main loop. */ |
| watch = qio_channel_add_watch(ioc, |
| G_IO_OUT, |
| nbd_negotiate_continue, |
| qemu_coroutine_self(), |
| NULL); |
| ret = write_sync(ioc, buffer, size); |
| g_source_remove(watch); |
| return ret; |
| } |
| |
| static ssize_t nbd_negotiate_drop_sync(QIOChannel *ioc, size_t size) |
| { |
| ssize_t ret, dropped = size; |
| uint8_t *buffer = g_malloc(MIN(65536, size)); |
| |
| while (size > 0) { |
| ret = nbd_negotiate_read(ioc, buffer, MIN(65536, size)); |
| if (ret < 0) { |
| g_free(buffer); |
| return ret; |
| } |
| |
| assert(ret <= size); |
| size -= ret; |
| } |
| |
| g_free(buffer); |
| return dropped; |
| } |
| |
| /* 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 a reply header, including length, but no payload. |
| * Return -errno on error, 0 on success. */ |
| static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type, |
| uint32_t opt, uint32_t len) |
| { |
| uint64_t magic; |
| |
| TRACE("Reply opt=%" PRIx32 " type=%" PRIx32 " len=%" PRIu32, |
| type, opt, len); |
| |
| magic = cpu_to_be64(NBD_REP_MAGIC); |
| if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) { |
| LOG("write failed (rep magic)"); |
| return -EINVAL; |
| } |
| opt = cpu_to_be32(opt); |
| if (nbd_negotiate_write(ioc, &opt, sizeof(opt)) != sizeof(opt)) { |
| LOG("write failed (rep opt)"); |
| return -EINVAL; |
| } |
| type = cpu_to_be32(type); |
| if (nbd_negotiate_write(ioc, &type, sizeof(type)) != sizeof(type)) { |
| LOG("write failed (rep type)"); |
| return -EINVAL; |
| } |
| len = cpu_to_be32(len); |
| if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) { |
| LOG("write failed (rep data length)"); |
| return -EINVAL; |
| } |
| return 0; |
| } |
| |
| /* Send a reply header with default 0 length. |
| * Return -errno on error, 0 on success. */ |
| static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt) |
| { |
| return nbd_negotiate_send_rep_len(ioc, type, opt, 0); |
| } |
| |
| /* Send an error reply. |
| * Return -errno on error, 0 on success. */ |
| static int GCC_FMT_ATTR(4, 5) |
| nbd_negotiate_send_rep_err(QIOChannel *ioc, uint32_t type, |
| uint32_t opt, const char *fmt, ...) |
| { |
| va_list va; |
| char *msg; |
| int ret; |
| size_t len; |
| |
| va_start(va, fmt); |
| msg = g_strdup_vprintf(fmt, va); |
| va_end(va); |
| len = strlen(msg); |
| assert(len < 4096); |
| TRACE("sending error message \"%s\"", msg); |
| ret = nbd_negotiate_send_rep_len(ioc, type, opt, len); |
| if (ret < 0) { |
| goto out; |
| } |
| if (nbd_negotiate_write(ioc, msg, len) != len) { |
| LOG("write failed (error message)"); |
| ret = -EIO; |
| } else { |
| ret = 0; |
| } |
| out: |
| g_free(msg); |
| return ret; |
| } |
| |
| /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. |
| * Return -errno on error, 0 on success. */ |
| static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp) |
| { |
| size_t name_len, desc_len; |
| uint32_t len; |
| const char *name = exp->name ? exp->name : ""; |
| const char *desc = exp->description ? exp->description : ""; |
| int rc; |
| |
| TRACE("Advertising export name '%s' description '%s'", name, desc); |
| name_len = strlen(name); |
| desc_len = strlen(desc); |
| len = name_len + desc_len + sizeof(len); |
| rc = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, len); |
| if (rc < 0) { |
| return rc; |
| } |
| |
| len = cpu_to_be32(name_len); |
| if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) { |
| LOG("write failed (name length)"); |
| return -EINVAL; |
| } |
| if (nbd_negotiate_write(ioc, name, name_len) != name_len) { |
| LOG("write failed (name buffer)"); |
| return -EINVAL; |
| } |
| if (nbd_negotiate_write(ioc, desc, desc_len) != desc_len) { |
| LOG("write failed (description buffer)"); |
| return -EINVAL; |
| } |
| return 0; |
| } |
| |
| /* Process the NBD_OPT_LIST command, with a potential series of replies. |
| * Return -errno on error, 0 on success. */ |
| static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length) |
| { |
| NBDExport *exp; |
| |
| if (length) { |
| if (nbd_negotiate_drop_sync(client->ioc, length) != length) { |
| return -EIO; |
| } |
| return nbd_negotiate_send_rep_err(client->ioc, |
| NBD_REP_ERR_INVALID, NBD_OPT_LIST, |
| "OPT_LIST should not have length"); |
| } |
| |
| /* For each export, send a NBD_REP_SERVER reply. */ |
| QTAILQ_FOREACH(exp, &exports, next) { |
| if (nbd_negotiate_send_rep_list(client->ioc, exp)) { |
| return -EINVAL; |
| } |
| } |
| /* Finish with a NBD_REP_ACK. */ |
| return nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_LIST); |
| } |
| |
| static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length) |
| { |
| int rc = -EINVAL; |
| char name[NBD_MAX_NAME_SIZE + 1]; |
| |
| /* Client sends: |
| [20 .. xx] export name (length bytes) |
| */ |
| TRACE("Checking length"); |
| if (length >= sizeof(name)) { |
| LOG("Bad length received"); |
| goto fail; |
| } |
| if (nbd_negotiate_read(client->ioc, name, length) != length) { |
| LOG("read failed"); |
| goto fail; |
| } |
| name[length] = '\0'; |
| |
| TRACE("Client requested export '%s'", name); |
| |
| client->exp = nbd_export_find(name); |
| if (!client->exp) { |
| LOG("export not found"); |
| goto fail; |
| } |
| |
| QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); |
| nbd_export_get(client->exp); |
| rc = 0; |
| fail: |
| return rc; |
| } |
| |
| /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the |
| * new channel for all further (now-encrypted) communication. */ |
| static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, |
| uint32_t length) |
| { |
| QIOChannel *ioc; |
| QIOChannelTLS *tioc; |
| struct NBDTLSHandshakeData data = { 0 }; |
| |
| TRACE("Setting up TLS"); |
| ioc = client->ioc; |
| if (length) { |
| if (nbd_negotiate_drop_sync(ioc, length) != length) { |
| return NULL; |
| } |
| nbd_negotiate_send_rep_err(ioc, NBD_REP_ERR_INVALID, NBD_OPT_STARTTLS, |
| "OPT_STARTTLS should not have length"); |
| return NULL; |
| } |
| |
| if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, |
| NBD_OPT_STARTTLS) < 0) { |
| return NULL; |
| } |
| |
| tioc = qio_channel_tls_new_server(ioc, |
| client->tlscreds, |
| client->tlsaclname, |
| NULL); |
| if (!tioc) { |
| return NULL; |
| } |
| |
| qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); |
| TRACE("Starting TLS handshake"); |
| data.loop = g_main_loop_new(g_main_context_default(), FALSE); |
| 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) { |
| object_unref(OBJECT(tioc)); |
| error_free(data.error); |
| return NULL; |
| } |
| |
| return QIO_CHANNEL(tioc); |
| } |
| |
| |
| /* Process all NBD_OPT_* client option commands. |
| * Return -errno on error, 0 on success. */ |
| static int nbd_negotiate_options(NBDClient *client) |
| { |
| uint32_t flags; |
| bool fixedNewstyle = false; |
| |
| /* Client sends: |
| [ 0 .. 3] client flags |
| |
| [ 0 .. 7] NBD_OPTS_MAGIC |
| [ 8 .. 11] NBD option |
| [12 .. 15] Data length |
| ... Rest of request |
| |
| [ 0 .. 7] NBD_OPTS_MAGIC |
| [ 8 .. 11] Second NBD option |
| [12 .. 15] Data length |
| ... Rest of request |
| */ |
| |
| if (nbd_negotiate_read(client->ioc, &flags, sizeof(flags)) != |
| sizeof(flags)) { |
| LOG("read failed"); |
| return -EIO; |
| } |
| TRACE("Checking client flags"); |
| be32_to_cpus(&flags); |
| if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { |
| TRACE("Client supports fixed newstyle handshake"); |
| fixedNewstyle = true; |
| flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; |
| } |
| if (flags & NBD_FLAG_C_NO_ZEROES) { |
| TRACE("Client supports no zeroes at handshake end"); |
| client->no_zeroes = true; |
| flags &= ~NBD_FLAG_C_NO_ZEROES; |
| } |
| if (flags != 0) { |
| TRACE("Unknown client flags 0x%" PRIx32 " received", flags); |
| return -EIO; |
| } |
| |
| while (1) { |
| int ret; |
| uint32_t clientflags, length; |
| uint64_t magic; |
| |
| if (nbd_negotiate_read(client->ioc, &magic, sizeof(magic)) != |
| sizeof(magic)) { |
| LOG("read failed"); |
| return -EINVAL; |
| } |
| TRACE("Checking opts magic"); |
| if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) { |
| LOG("Bad magic received"); |
| return -EINVAL; |
| } |
| |
| if (nbd_negotiate_read(client->ioc, &clientflags, |
| sizeof(clientflags)) != sizeof(clientflags)) { |
| LOG("read failed"); |
| return -EINVAL; |
| } |
| clientflags = be32_to_cpu(clientflags); |
| |
| if (nbd_negotiate_read(client->ioc, &length, sizeof(length)) != |
| sizeof(length)) { |
| LOG("read failed"); |
| return -EINVAL; |
| } |
| length = be32_to_cpu(length); |
| |
| TRACE("Checking option 0x%" PRIx32, clientflags); |
| if (client->tlscreds && |
| client->ioc == (QIOChannel *)client->sioc) { |
| QIOChannel *tioc; |
| if (!fixedNewstyle) { |
| TRACE("Unsupported option 0x%" PRIx32, clientflags); |
| return -EINVAL; |
| } |
| switch (clientflags) { |
| case NBD_OPT_STARTTLS: |
| tioc = nbd_negotiate_handle_starttls(client, length); |
| if (!tioc) { |
| return -EIO; |
| } |
| object_unref(OBJECT(client->ioc)); |
| client->ioc = QIO_CHANNEL(tioc); |
| break; |
| |
| case NBD_OPT_EXPORT_NAME: |
| /* No way to return an error to client, so drop connection */ |
| TRACE("Option 0x%x not permitted before TLS", clientflags); |
| return -EINVAL; |
| |
| default: |
| if (nbd_negotiate_drop_sync(client->ioc, length) != length) { |
| return -EIO; |
| } |
| ret = nbd_negotiate_send_rep_err(client->ioc, |
| NBD_REP_ERR_TLS_REQD, |
| clientflags, |
| "Option 0x%" PRIx32 |
| "not permitted before TLS", |
| clientflags); |
| if (ret < 0) { |
| return ret; |
| } |
| /* Let the client keep trying, unless they asked to quit */ |
| if (clientflags == NBD_OPT_ABORT) { |
| return -EINVAL; |
| } |
| break; |
| } |
| } else if (fixedNewstyle) { |
| switch (clientflags) { |
| case NBD_OPT_LIST: |
| ret = nbd_negotiate_handle_list(client, length); |
| if (ret < 0) { |
| return ret; |
| } |
| break; |
| |
| case NBD_OPT_ABORT: |
| /* NBD spec says we must try to reply before |
| * disconnecting, but that we must also tolerate |
| * guests that don't wait for our reply. */ |
| nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, clientflags); |
| return -EINVAL; |
| |
| case NBD_OPT_EXPORT_NAME: |
| return nbd_negotiate_handle_export_name(client, length); |
| |
| case NBD_OPT_STARTTLS: |
| if (nbd_negotiate_drop_sync(client->ioc, length) != length) { |
| return -EIO; |
| } |
| if (client->tlscreds) { |
| ret = nbd_negotiate_send_rep_err(client->ioc, |
| NBD_REP_ERR_INVALID, |
| clientflags, |
| "TLS already enabled"); |
| } else { |
| ret = nbd_negotiate_send_rep_err(client->ioc, |
| NBD_REP_ERR_POLICY, |
| clientflags, |
| "TLS not configured"); |
| } |
| if (ret < 0) { |
| return ret; |
| } |
| break; |
| default: |
| if (nbd_negotiate_drop_sync(client->ioc, length) != length) { |
| return -EIO; |
| } |
| ret = nbd_negotiate_send_rep_err(client->ioc, |
| NBD_REP_ERR_UNSUP, |
| clientflags, |
| "Unsupported option 0x%" |
| PRIx32, |
| clientflags); |
| if (ret < 0) { |
| return ret; |
| } |
| break; |
| } |
| } else { |
| /* |
| * If broken new-style we should drop the connection |
| * for anything except NBD_OPT_EXPORT_NAME |
| */ |
| switch (clientflags) { |
| case NBD_OPT_EXPORT_NAME: |
| return nbd_negotiate_handle_export_name(client, length); |
| |
| default: |
| TRACE("Unsupported option 0x%" PRIx32, clientflags); |
| return -EINVAL; |
| } |
| } |
| } |
| } |
| |
| typedef struct { |
| NBDClient *client; |
| Coroutine *co; |
| } NBDClientNewData; |
| |
| static coroutine_fn int nbd_negotiate(NBDClientNewData *data) |
| { |
| NBDClient *client = data->client; |
| char buf[8 + 8 + 8 + 128]; |
| int rc; |
| const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | |
| NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA | |
| NBD_FLAG_SEND_WRITE_ZEROES); |
| bool oldStyle; |
| size_t len; |
| |
| /* Old style negotiation header without options |
| [ 0 .. 7] passwd ("NBDMAGIC") |
| [ 8 .. 15] magic (NBD_CLIENT_MAGIC) |
| [16 .. 23] size |
| [24 .. 25] server flags (0) |
| [26 .. 27] export flags |
| [28 .. 151] reserved (0) |
| |
| New style negotiation header with options |
| [ 0 .. 7] passwd ("NBDMAGIC") |
| [ 8 .. 15] magic (NBD_OPTS_MAGIC) |
| [16 .. 17] server flags (0) |
| ....options sent.... |
| [18 .. 25] size |
| [26 .. 27] export flags |
| [28 .. 151] reserved (0, omit if no_zeroes) |
| */ |
| |
| qio_channel_set_blocking(client->ioc, false, NULL); |
| rc = -EINVAL; |
| |
| TRACE("Beginning negotiation."); |
| memset(buf, 0, sizeof(buf)); |
| memcpy(buf, "NBDMAGIC", 8); |
| |
| oldStyle = client->exp != NULL && !client->tlscreds; |
| if (oldStyle) { |
| TRACE("advertising size %" PRIu64 " and flags %x", |
| client->exp->size, client->exp->nbdflags | myflags); |
| stq_be_p(buf + 8, NBD_CLIENT_MAGIC); |
| stq_be_p(buf + 16, client->exp->size); |
| stw_be_p(buf + 26, client->exp->nbdflags | myflags); |
| } else { |
| stq_be_p(buf + 8, NBD_OPTS_MAGIC); |
| stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); |
| } |
| |
| if (oldStyle) { |
| if (client->tlscreds) { |
| TRACE("TLS cannot be enabled with oldstyle protocol"); |
| goto fail; |
| } |
| if (nbd_negotiate_write(client->ioc, buf, sizeof(buf)) != sizeof(buf)) { |
| LOG("write failed"); |
| goto fail; |
| } |
| } else { |
| if (nbd_negotiate_write(client->ioc, buf, 18) != 18) { |
| LOG("write failed"); |
| goto fail; |
| } |
| rc = nbd_negotiate_options(client); |
| if (rc != 0) { |
| LOG("option negotiation failed"); |
| goto fail; |
| } |
| |
| TRACE("advertising size %" PRIu64 " and flags %x", |
| client->exp->size, client->exp->nbdflags | myflags); |
| stq_be_p(buf + 18, client->exp->size); |
| stw_be_p(buf + 26, client->exp->nbdflags | myflags); |
| len = client->no_zeroes ? 10 : sizeof(buf) - 18; |
| if (nbd_negotiate_write(client->ioc, buf + 18, len) != len) { |
| LOG("write failed"); |
| goto fail; |
| } |
| } |
| |
| TRACE("Negotiation succeeded."); |
| rc = 0; |
| fail: |
| return rc; |
| } |
| |
| static ssize_t nbd_receive_request(QIOChannel *ioc, NBDRequest *request) |
| { |
| uint8_t buf[NBD_REQUEST_SIZE]; |
| uint32_t magic; |
| ssize_t ret; |
| |
| ret = read_sync(ioc, buf, sizeof(buf)); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| if (ret != sizeof(buf)) { |
| LOG("read failed"); |
| return -EINVAL; |
| } |
| |
| /* Request |
| [ 0 .. 3] magic (NBD_REQUEST_MAGIC) |
| [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) |
| [ 6 .. 7] type (NBD_CMD_READ, ...) |
| [ 8 .. 15] handle |
| [16 .. 23] from |
| [24 .. 27] len |
| */ |
| |
| magic = ldl_be_p(buf); |
| request->flags = lduw_be_p(buf + 4); |
| request->type = lduw_be_p(buf + 6); |
| request->handle = ldq_be_p(buf + 8); |
| request->from = ldq_be_p(buf + 16); |
| request->len = ldl_be_p(buf + 24); |
| |
| TRACE("Got request: { magic = 0x%" PRIx32 ", .flags = %" PRIx16 |
| ", .type = %" PRIx16 ", from = %" PRIu64 ", len = %" PRIu32 " }", |
| magic, request->flags, request->type, request->from, request->len); |
| |
| if (magic != NBD_REQUEST_MAGIC) { |
| LOG("invalid magic (got 0x%" PRIx32 ")", magic); |
| return -EINVAL; |
| } |
| return 0; |
| } |
| |
| static ssize_t nbd_send_reply(QIOChannel *ioc, NBDReply *reply) |
| { |
| uint8_t buf[NBD_REPLY_SIZE]; |
| ssize_t ret; |
| |
| reply->error = system_errno_to_nbd_errno(reply->error); |
| |
| TRACE("Sending response to client: { .error = %" PRId32 |
| ", handle = %" PRIu64 " }", |
| reply->error, reply->handle); |
| |
| /* Reply |
| [ 0 .. 3] magic (NBD_REPLY_MAGIC) |
| [ 4 .. 7] error (0 == no error) |
| [ 7 .. 15] handle |
| */ |
| stl_be_p(buf, NBD_REPLY_MAGIC); |
| stl_be_p(buf + 4, reply->error); |
| stq_be_p(buf + 8, reply->handle); |
| |
| ret = write_sync(ioc, buf, sizeof(buf)); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| if (ret != sizeof(buf)) { |
| LOG("writing to socket failed"); |
| return -EINVAL; |
| } |
| return 0; |
| } |
| |
| #define MAX_NBD_REQUESTS 16 |
| |
| void nbd_client_get(NBDClient *client) |
| { |
| client->refcount++; |
| } |
| |
| void nbd_client_put(NBDClient *client) |
| { |
| if (--client->refcount == 0) { |
| /* The last reference should be dropped by client->close, |
| * which is called by client_close. |
| */ |
| assert(client->closing); |
| |
| qio_channel_detach_aio_context(client->ioc); |
| object_unref(OBJECT(client->sioc)); |
| object_unref(OBJECT(client->ioc)); |
| if (client->tlscreds) { |
| object_unref(OBJECT(client->tlscreds)); |
| } |
| g_free(client->tlsaclname); |
| if (client->exp) { |
| QTAILQ_REMOVE(&client->exp->clients, client, next); |
| nbd_export_put(client->exp); |
| } |
| g_free(client); |
| } |
| } |
| |
| static void client_close(NBDClient *client) |
| { |
| if (client->closing) { |
| return; |
| } |
| |
| client->closing = true; |
| |
| /* Force requests to finish. They will drop their own references, |
| * then we'll close the socket and free the NBDClient. |
| */ |
| qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, |
| NULL); |
| |
| /* Also tell the client, so that they release their reference. */ |
| if (client->close) { |
| client->close(client); |
| } |
| } |
| |
| static NBDRequestData *nbd_request_get(NBDClient *client) |
| { |
| NBDRequestData *req; |
| |
| assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); |
| client->nb_requests++; |
| |
| req = g_new0(NBDRequestData, 1); |
| nbd_client_get(client); |
| req->client = client; |
| return req; |
| } |
| |
| static void nbd_request_put(NBDRequestData *req) |
| { |
| NBDClient *client = req->client; |
| |
| if (req->data) { |
| qemu_vfree(req->data); |
| } |
| g_free(req); |
| |
| client->nb_requests--; |
| nbd_client_receive_next_request(client); |
| |
| nbd_client_put(client); |
| } |
| |
| static void blk_aio_attached(AioContext *ctx, void *opaque) |
| { |
| NBDExport *exp = opaque; |
| NBDClient *client; |
| |
| TRACE("Export %s: Attaching clients to AIO context %p\n", exp->name, ctx); |
| |
| exp->ctx = ctx; |
| |
| QTAILQ_FOREACH(client, &exp->clients, next) { |
| qio_channel_attach_aio_context(client->ioc, ctx); |
| if (client->recv_coroutine) { |
| aio_co_schedule(ctx, client->recv_coroutine); |
| } |
| if (client->send_coroutine) { |
| aio_co_schedule(ctx, client->send_coroutine); |
| } |
| } |
| } |
| |
| static void blk_aio_detach(void *opaque) |
| { |
| NBDExport *exp = opaque; |
| NBDClient *client; |
| |
| TRACE("Export %s: Detaching clients from AIO context %p\n", exp->name, exp->ctx); |
| |
| QTAILQ_FOREACH(client, &exp->clients, next) { |
| qio_channel_detach_aio_context(client->ioc); |
| } |
| |
| exp->ctx = NULL; |
| } |
| |
| static void nbd_eject_notifier(Notifier *n, void *data) |
| { |
| NBDExport *exp = container_of(n, NBDExport, eject_notifier); |
| nbd_export_close(exp); |
| } |
| |
| NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size, |
| uint16_t nbdflags, void (*close)(NBDExport *), |
| bool writethrough, BlockBackend *on_eject_blk, |
| Error **errp) |
| { |
| BlockBackend *blk; |
| NBDExport *exp = g_malloc0(sizeof(NBDExport)); |
| uint64_t perm; |
| int ret; |
| |
| /* Don't allow resize while the NBD server is running, otherwise we don't |
| * care what happens with the node. */ |
| perm = BLK_PERM_CONSISTENT_READ; |
| if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) { |
| perm |= BLK_PERM_WRITE; |
| } |
| blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | |
| BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); |
| ret = blk_insert_bs(blk, bs, errp); |
| if (ret < 0) { |
| goto fail; |
| } |
| blk_set_enable_write_cache(blk, !writethrough); |
| |
| exp->refcount = 1; |
| QTAILQ_INIT(&exp->clients); |
| exp->blk = blk; |
| exp->dev_offset = dev_offset; |
| exp->nbdflags = nbdflags; |
| exp->size = size < 0 ? blk_getlength(blk) : size; |
| if (exp->size < 0) { |
| error_setg_errno(errp, -exp->size, |
| "Failed to determine the NBD export's length"); |
| goto fail; |
| } |
| exp->size -= exp->size % BDRV_SECTOR_SIZE; |
| |
| exp->close = close; |
| exp->ctx = blk_get_aio_context(blk); |
| blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); |
| |
| if (on_eject_blk) { |
| blk_ref(on_eject_blk); |
| exp->eject_notifier_blk = on_eject_blk; |
| exp->eject_notifier.notify = nbd_eject_notifier; |
| blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier); |
| } |
| |
| /* |
| * NBD exports are used for non-shared storage migration. Make sure |
| * that BDRV_O_INACTIVE is cleared and the image is ready for write |
| * access since the export could be available before migration handover. |
| */ |
| aio_context_acquire(exp->ctx); |
| blk_invalidate_cache(blk, NULL); |
| aio_context_release(exp->ctx); |
| return exp; |
| |
| fail: |
| blk_unref(blk); |
| g_free(exp); |
| return NULL; |
| } |
| |
| NBDExport *nbd_export_find(const char *name) |
| { |
| NBDExport *exp; |
| QTAILQ_FOREACH(exp, &exports, next) { |
| if (strcmp(name, exp->name) == 0) { |
| return exp; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| void nbd_export_set_name(NBDExport *exp, const char *name) |
| { |
| if (exp->name == name) { |
| return; |
| } |
| |
| nbd_export_get(exp); |
| if (exp->name != NULL) { |
| g_free(exp->name); |
| exp->name = NULL; |
| QTAILQ_REMOVE(&exports, exp, next); |
| nbd_export_put(exp); |
| } |
| if (name != NULL) { |
| nbd_export_get(exp); |
| exp->name = g_strdup(name); |
| QTAILQ_INSERT_TAIL(&exports, exp, next); |
| } |
| nbd_export_put(exp); |
| } |
| |
| void nbd_export_set_description(NBDExport *exp, const char *description) |
| { |
| g_free(exp->description); |
| exp->description = g_strdup(description); |
| } |
| |
| void nbd_export_close(NBDExport *exp) |
| { |
| NBDClient *client, *next; |
| |
| nbd_export_get(exp); |
| QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { |
| client_close(client); |
| } |
| nbd_export_set_name(exp, NULL); |
| nbd_export_set_description(exp, NULL); |
| nbd_export_put(exp); |
| } |
| |
| void nbd_export_get(NBDExport *exp) |
| { |
| assert(exp->refcount > 0); |
| exp->refcount++; |
| } |
| |
| void nbd_export_put(NBDExport *exp) |
| { |
| assert(exp->refcount > 0); |
| if (exp->refcount == 1) { |
| nbd_export_close(exp); |
| } |
| |
| if (--exp->refcount == 0) { |
| assert(exp->name == NULL); |
| assert(exp->description == NULL); |
| |
| if (exp->close) { |
| exp->close(exp); |
| } |
| |
| if (exp->blk) { |
| if (exp->eject_notifier_blk) { |
| notifier_remove(&exp->eject_notifier); |
| blk_unref(exp->eject_notifier_blk); |
| } |
| blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, |
| blk_aio_detach, exp); |
| blk_unref(exp->blk); |
| exp->blk = NULL; |
| } |
| |
| g_free(exp); |
| } |
| } |
| |
| BlockBackend *nbd_export_get_blockdev(NBDExport *exp) |
| { |
| return exp->blk; |
| } |
| |
| void nbd_export_close_all(void) |
| { |
| NBDExport *exp, *next; |
| |
| QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { |
| nbd_export_close(exp); |
| } |
| } |
| |
| static ssize_t nbd_co_send_reply(NBDRequestData *req, NBDReply *reply, |
| int len) |
| { |
| NBDClient *client = req->client; |
| ssize_t rc, ret; |
| |
| g_assert(qemu_in_coroutine()); |
| qemu_co_mutex_lock(&client->send_lock); |
| client->send_coroutine = qemu_coroutine_self(); |
| |
| if (!len) { |
| rc = nbd_send_reply(client->ioc, reply); |
| } else { |
| qio_channel_set_cork(client->ioc, true); |
| rc = nbd_send_reply(client->ioc, reply); |
| if (rc >= 0) { |
| ret = write_sync(client->ioc, req->data, len); |
| if (ret != len) { |
| rc = -EIO; |
| } |
| } |
| qio_channel_set_cork(client->ioc, false); |
| } |
| |
| client->send_coroutine = NULL; |
| qemu_co_mutex_unlock(&client->send_lock); |
| return rc; |
| } |
| |
| /* Collect a client request. Return 0 if request looks valid, -EAGAIN |
| * to keep trying the collection, -EIO to drop connection right away, |
| * and any other negative value to report an error to the client |
| * (although the caller may still need to disconnect after reporting |
| * the error). */ |
| static ssize_t nbd_co_receive_request(NBDRequestData *req, |
| NBDRequest *request) |
| { |
| NBDClient *client = req->client; |
| ssize_t rc; |
| |
| g_assert(qemu_in_coroutine()); |
| assert(client->recv_coroutine == qemu_coroutine_self()); |
| rc = nbd_receive_request(client->ioc, request); |
| if (rc < 0) { |
| if (rc != -EAGAIN) { |
| rc = -EIO; |
| } |
| goto out; |
| } |
| |
| TRACE("Decoding type"); |
| |
| if (request->type != NBD_CMD_WRITE) { |
| /* No payload, we are ready to read the next request. */ |
| req->complete = true; |
| } |
| |
| if (request->type == NBD_CMD_DISC) { |
| /* Special case: we're going to disconnect without a reply, |
| * whether or not flags, from, or len are bogus */ |
| TRACE("Request type is DISCONNECT"); |
| rc = -EIO; |
| goto out; |
| } |
| |
| /* Check for sanity in the parameters, part 1. Defer as many |
| * checks as possible until after reading any NBD_CMD_WRITE |
| * payload, so we can try and keep the connection alive. */ |
| if ((request->from + request->len) < request->from) { |
| LOG("integer overflow detected, you're probably being attacked"); |
| rc = -EINVAL; |
| goto out; |
| } |
| |
| if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE) { |
| if (request->len > NBD_MAX_BUFFER_SIZE) { |
| LOG("len (%" PRIu32" ) is larger than max len (%u)", |
| request->len, NBD_MAX_BUFFER_SIZE); |
| rc = -EINVAL; |
| goto out; |
| } |
| |
| req->data = blk_try_blockalign(client->exp->blk, request->len); |
| if (req->data == NULL) { |
| rc = -ENOMEM; |
| goto out; |
| } |
| } |
| if (request->type == NBD_CMD_WRITE) { |
| TRACE("Reading %" PRIu32 " byte(s)", request->len); |
| |
| if (read_sync(client->ioc, req->data, request->len) != request->len) { |
| LOG("reading from socket failed"); |
| rc = -EIO; |
| goto out; |
| } |
| req->complete = true; |
| } |
| |
| /* Sanity checks, part 2. */ |
| if (request->from + request->len > client->exp->size) { |
| LOG("operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 |
| ", Size: %" PRIu64, request->from, request->len, |
| (uint64_t)client->exp->size); |
| rc = request->type == NBD_CMD_WRITE ? -ENOSPC : -EINVAL; |
| goto out; |
| } |
| if (request->flags & ~(NBD_CMD_FLAG_FUA | NBD_CMD_FLAG_NO_HOLE)) { |
| LOG("unsupported flags (got 0x%x)", request->flags); |
| rc = -EINVAL; |
| goto out; |
| } |
| if (request->type != NBD_CMD_WRITE_ZEROES && |
| (request->flags & NBD_CMD_FLAG_NO_HOLE)) { |
| LOG("unexpected flags (got 0x%x)", request->flags); |
| rc = -EINVAL; |
| goto out; |
| } |
| |
| rc = 0; |
| |
| out: |
| client->recv_coroutine = NULL; |
| nbd_client_receive_next_request(client); |
| |
| return rc; |
| } |
| |
| /* Owns a reference to the NBDClient passed as opaque. */ |
| static coroutine_fn void nbd_trip(void *opaque) |
| { |
| NBDClient *client = opaque; |
| NBDExport *exp = client->exp; |
| NBDRequestData *req; |
| NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ |
| NBDReply reply; |
| ssize_t ret; |
| int flags; |
| |
| TRACE("Reading request."); |
| if (client->closing) { |
| nbd_client_put(client); |
| return; |
| } |
| |
| req = nbd_request_get(client); |
| ret = nbd_co_receive_request(req, &request); |
| if (ret == -EAGAIN) { |
| goto done; |
| } |
| if (ret == -EIO) { |
| goto out; |
| } |
| |
| reply.handle = request.handle; |
| reply.error = 0; |
| |
| if (ret < 0) { |
| reply.error = -ret; |
| goto error_reply; |
| } |
| |
| if (client->closing) { |
| /* |
| * The client may be closed when we are blocked in |
| * nbd_co_receive_request() |
| */ |
| goto done; |
| } |
| |
| switch (request.type) { |
| case NBD_CMD_READ: |
| TRACE("Request type is READ"); |
| |
| /* XXX: NBD Protocol only documents use of FUA with WRITE */ |
| if (request.flags & NBD_CMD_FLAG_FUA) { |
| ret = blk_co_flush(exp->blk); |
| if (ret < 0) { |
| LOG("flush failed"); |
| reply.error = -ret; |
| goto error_reply; |
| } |
| } |
| |
| ret = blk_pread(exp->blk, request.from + exp->dev_offset, |
| req->data, request.len); |
| if (ret < 0) { |
| LOG("reading from file failed"); |
| reply.error = -ret; |
| goto error_reply; |
| } |
| |
| TRACE("Read %" PRIu32" byte(s)", request.len); |
| if (nbd_co_send_reply(req, &reply, request.len) < 0) |
| goto out; |
| break; |
| case NBD_CMD_WRITE: |
| TRACE("Request type is WRITE"); |
| |
| if (exp->nbdflags & NBD_FLAG_READ_ONLY) { |
| TRACE("Server is read-only, return error"); |
| reply.error = EROFS; |
| goto error_reply; |
| } |
| |
| TRACE("Writing to device"); |
| |
| flags = 0; |
| if (request.flags & NBD_CMD_FLAG_FUA) { |
| flags |= BDRV_REQ_FUA; |
| } |
| ret = blk_pwrite(exp->blk, request.from + exp->dev_offset, |
| req->data, request.len, flags); |
| if (ret < 0) { |
| LOG("writing to file failed"); |
| reply.error = -ret; |
| goto error_reply; |
| } |
| |
| if (nbd_co_send_reply(req, &reply, 0) < 0) { |
| goto out; |
| } |
| break; |
| |
| case NBD_CMD_WRITE_ZEROES: |
| TRACE("Request type is WRITE_ZEROES"); |
| |
| if (exp->nbdflags & NBD_FLAG_READ_ONLY) { |
| TRACE("Server is read-only, return error"); |
| reply.error = EROFS; |
| goto error_reply; |
| } |
| |
| TRACE("Writing to device"); |
| |
| flags = 0; |
| if (request.flags & NBD_CMD_FLAG_FUA) { |
| flags |= BDRV_REQ_FUA; |
| } |
| if (!(request.flags & NBD_CMD_FLAG_NO_HOLE)) { |
| flags |= BDRV_REQ_MAY_UNMAP; |
| } |
| ret = blk_pwrite_zeroes(exp->blk, request.from + exp->dev_offset, |
| request.len, flags); |
| if (ret < 0) { |
| LOG("writing to file failed"); |
| reply.error = -ret; |
| goto error_reply; |
| } |
| |
| if (nbd_co_send_reply(req, &reply, 0) < 0) { |
| goto out; |
| } |
| break; |
| |
| case NBD_CMD_DISC: |
| /* unreachable, thanks to special case in nbd_co_receive_request() */ |
| abort(); |
| |
| case NBD_CMD_FLUSH: |
| TRACE("Request type is FLUSH"); |
| |
| ret = blk_co_flush(exp->blk); |
| if (ret < 0) { |
| LOG("flush failed"); |
| reply.error = -ret; |
| } |
| if (nbd_co_send_reply(req, &reply, 0) < 0) { |
| goto out; |
| } |
| break; |
| case NBD_CMD_TRIM: |
| TRACE("Request type is TRIM"); |
| ret = blk_co_pdiscard(exp->blk, request.from + exp->dev_offset, |
| request.len); |
| if (ret < 0) { |
| LOG("discard failed"); |
| reply.error = -ret; |
| } |
| if (nbd_co_send_reply(req, &reply, 0) < 0) { |
| goto out; |
| } |
| break; |
| default: |
| LOG("invalid request type (%" PRIu32 ") received", request.type); |
| reply.error = EINVAL; |
| error_reply: |
| /* We must disconnect after NBD_CMD_WRITE if we did not |
| * read the payload. |
| */ |
| if (nbd_co_send_reply(req, &reply, 0) < 0 || !req->complete) { |
| goto out; |
| } |
| break; |
| } |
| |
| TRACE("Request/Reply complete"); |
| |
| done: |
| nbd_request_put(req); |
| nbd_client_put(client); |
| return; |
| |
| out: |
| nbd_request_put(req); |
| client_close(client); |
| nbd_client_put(client); |
| } |
| |
| static void nbd_client_receive_next_request(NBDClient *client) |
| { |
| if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { |
| nbd_client_get(client); |
| client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); |
| aio_co_schedule(client->exp->ctx, client->recv_coroutine); |
| } |
| } |
| |
| static coroutine_fn void nbd_co_client_start(void *opaque) |
| { |
| NBDClientNewData *data = opaque; |
| NBDClient *client = data->client; |
| NBDExport *exp = client->exp; |
| |
| if (exp) { |
| nbd_export_get(exp); |
| } |
| if (nbd_negotiate(data)) { |
| client_close(client); |
| goto out; |
| } |
| qemu_co_mutex_init(&client->send_lock); |
| |
| if (exp) { |
| QTAILQ_INSERT_TAIL(&exp->clients, client, next); |
| } |
| |
| nbd_client_receive_next_request(client); |
| |
| out: |
| g_free(data); |
| } |
| |
| void nbd_client_new(NBDExport *exp, |
| QIOChannelSocket *sioc, |
| QCryptoTLSCreds *tlscreds, |
| const char *tlsaclname, |
| void (*close_fn)(NBDClient *)) |
| { |
| NBDClient *client; |
| NBDClientNewData *data = g_new(NBDClientNewData, 1); |
| |
| client = g_malloc0(sizeof(NBDClient)); |
| client->refcount = 1; |
| client->exp = exp; |
| client->tlscreds = tlscreds; |
| if (tlscreds) { |
| object_ref(OBJECT(client->tlscreds)); |
| } |
| client->tlsaclname = g_strdup(tlsaclname); |
| client->sioc = sioc; |
| object_ref(OBJECT(client->sioc)); |
| client->ioc = QIO_CHANNEL(sioc); |
| object_ref(OBJECT(client->ioc)); |
| client->close = close_fn; |
| |
| data->client = client; |
| data->co = qemu_coroutine_create(nbd_co_client_start, data); |
| qemu_coroutine_enter(data->co); |
| } |
