--- /dev/null
+/*
+ * 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 EINVAL:
+ default:
+ return NBD_EINVAL;
+ }
+}
+
+/* Definitions for opaque data types */
+
+typedef struct NBDRequest NBDRequest;
+
+struct NBDRequest {
+ QSIMPLEQ_ENTRY(NBDRequest) entry;
+ NBDClient *client;
+ uint8_t *data;
+};
+
+struct NBDExport {
+ int refcount;
+ void (*close)(NBDExport *exp);
+
+ BlockBackend *blk;
+ char *name;
+ off_t dev_offset;
+ off_t size;
+ uint32_t nbdflags;
+ QTAILQ_HEAD(, NBDClient) clients;
+ QTAILQ_ENTRY(NBDExport) next;
+
+ AioContext *ctx;
+
+ Notifier eject_notifier;
+};
+
+static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
+
+struct NBDClient {
+ int refcount;
+ void (*close)(NBDClient *client);
+
+ 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;
+
+ bool can_read;
+
+ QTAILQ_ENTRY(NBDClient) next;
+ int nb_requests;
+ bool closing;
+};
+
+/* That's all folks */
+
+static void nbd_set_handlers(NBDClient *client);
+static void nbd_unset_handlers(NBDClient *client);
+static void nbd_update_can_read(NBDClient *client);
+
+static gboolean nbd_negotiate_continue(QIOChannel *ioc,
+ GIOCondition condition,
+ void *opaque)
+{
+ qemu_coroutine_enter(opaque, NULL);
+ 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, 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)
+
+*/
+
+static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt)
+{
+ uint64_t magic;
+ uint32_t len;
+
+ TRACE("Reply opt=%x type=%x", type, opt);
+
+ 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(0);
+ if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
+ LOG("write failed (rep data length)");
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
+{
+ uint64_t magic, name_len;
+ uint32_t opt, type, len;
+
+ TRACE("Advertizing export name '%s'", exp->name ? exp->name : "");
+ name_len = strlen(exp->name);
+ magic = cpu_to_be64(NBD_REP_MAGIC);
+ if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
+ LOG("write failed (magic)");
+ return -EINVAL;
+ }
+ opt = cpu_to_be32(NBD_OPT_LIST);
+ if (nbd_negotiate_write(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
+ LOG("write failed (opt)");
+ return -EINVAL;
+ }
+ type = cpu_to_be32(NBD_REP_SERVER);
+ if (nbd_negotiate_write(ioc, &type, sizeof(type)) != sizeof(type)) {
+ LOG("write failed (reply type)");
+ return -EINVAL;
+ }
+ len = cpu_to_be32(name_len + sizeof(len));
+ if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
+ LOG("write failed (length)");
+ return -EINVAL;
+ }
+ len = cpu_to_be32(name_len);
+ if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
+ LOG("write failed (length)");
+ return -EINVAL;
+ }
+ if (nbd_negotiate_write(ioc, exp->name, name_len) != name_len) {
+ LOG("write failed (buffer)");
+ return -EINVAL;
+ }
+ return 0;
+}
+
+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(client->ioc,
+ NBD_REP_ERR_INVALID, NBD_OPT_LIST);
+ }
+
+ /* 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[256];
+
+ /* Client sends:
+ [20 .. xx] export name (length bytes)
+ */
+ TRACE("Checking length");
+ if (length > 255) {
+ 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;
+}
+
+
+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(ioc, NBD_REP_ERR_INVALID, NBD_OPT_STARTTLS);
+ return NULL;
+ }
+
+ nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_STARTTLS);
+
+ tioc = qio_channel_tls_new_server(ioc,
+ client->tlscreds,
+ client->tlsaclname,
+ NULL);
+ if (!tioc) {
+ return NULL;
+ }
+
+ 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);
+}
+
+
+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("Support supports fixed newstyle handshake");
+ fixedNewstyle = true;
+ flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
+ }
+ if (flags != 0) {
+ TRACE("Unknown client flags 0x%x 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%x", clientflags);
+ if (client->tlscreds &&
+ client->ioc == (QIOChannel *)client->sioc) {
+ QIOChannel *tioc;
+ if (!fixedNewstyle) {
+ TRACE("Unsupported option 0x%x", 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:
+ TRACE("Option 0x%x not permitted before TLS", clientflags);
+ if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
+ return -EIO;
+ }
+ nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_TLS_REQD,
+ clientflags);
+ 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:
+ 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) {
+ TRACE("TLS already enabled");
+ nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_INVALID,
+ clientflags);
+ } else {
+ TRACE("TLS not configured");
+ nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_POLICY,
+ clientflags);
+ }
+ break;
+ default:
+ TRACE("Unsupported option 0x%x", clientflags);
+ if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
+ return -EIO;
+ }
+ nbd_negotiate_send_rep(client->ioc, NBD_REP_ERR_UNSUP,
+ clientflags);
+ 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%x", 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 int myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
+ NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA);
+ bool oldStyle;
+
+ /* 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)
+ */
+
+ 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) {
+ assert ((client->exp->nbdflags & ~65535) == 0);
+ 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);
+ }
+
+ 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;
+ }
+
+ assert ((client->exp->nbdflags & ~65535) == 0);
+ stq_be_p(buf + 18, client->exp->size);
+ stw_be_p(buf + 26, client->exp->nbdflags | myflags);
+ if (nbd_negotiate_write(client->ioc, buf + 18, sizeof(buf) - 18) !=
+ sizeof(buf) - 18) {
+ LOG("write failed");
+ goto fail;
+ }
+ }
+
+ TRACE("Negotiation succeeded.");
+ rc = 0;
+fail:
+ return rc;
+}
+
+#ifdef __linux__
+
+int nbd_disconnect(int fd)
+{
+ ioctl(fd, NBD_CLEAR_QUE);
+ ioctl(fd, NBD_DISCONNECT);
+ ioctl(fd, NBD_CLEAR_SOCK);
+ return 0;
+}
+
+#else
+
+int nbd_disconnect(int fd)
+{
+ return -ENOTSUP;
+}
+#endif
+
+static ssize_t nbd_receive_request(QIOChannel *ioc, struct nbd_request *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 .. 7] type (0 == READ, 1 == WRITE)
+ [ 8 .. 15] handle
+ [16 .. 23] from
+ [24 .. 27] len
+ */
+
+ magic = be32_to_cpup((uint32_t*)buf);
+ request->type = be32_to_cpup((uint32_t*)(buf + 4));
+ request->handle = be64_to_cpup((uint64_t*)(buf + 8));
+ request->from = be64_to_cpup((uint64_t*)(buf + 16));
+ request->len = be32_to_cpup((uint32_t*)(buf + 24));
+
+ TRACE("Got request: "
+ "{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",
+ magic, request->type, request->from, request->len);
+
+ if (magic != NBD_REQUEST_MAGIC) {
+ LOG("invalid magic (got 0x%x)", magic);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static ssize_t nbd_send_reply(QIOChannel *ioc, struct nbd_reply *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 = %d, 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);
+
+ nbd_unset_handlers(client);
+ 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 NBDRequest *nbd_request_get(NBDClient *client)
+{
+ NBDRequest *req;
+
+ assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
+ client->nb_requests++;
+ nbd_update_can_read(client);
+
+ req = g_new0(NBDRequest, 1);
+ nbd_client_get(client);
+ req->client = client;
+ return req;
+}
+
+static void nbd_request_put(NBDRequest *req)
+{
+ NBDClient *client = req->client;
+
+ if (req->data) {
+ qemu_vfree(req->data);
+ }
+ g_free(req);
+
+ client->nb_requests--;
+ nbd_update_can_read(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) {
+ nbd_set_handlers(client);
+ }
+}
+
+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) {
+ nbd_unset_handlers(client);
+ }
+
+ 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(BlockBackend *blk, off_t dev_offset, off_t size,
+ uint32_t nbdflags, void (*close)(NBDExport *),
+ Error **errp)
+{
+ NBDExport *exp = g_malloc0(sizeof(NBDExport));
+ 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_ref(blk);
+ blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
+
+ exp->eject_notifier.notify = nbd_eject_notifier;
+ blk_add_remove_bs_notifier(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:
+ 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_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_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);
+
+ if (exp->close) {
+ exp->close(exp);
+ }
+
+ if (exp->blk) {
+ notifier_remove(&exp->eject_notifier);
+ 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(NBDRequest *req, struct nbd_reply *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();
+ nbd_set_handlers(client);
+
+ 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;
+ nbd_set_handlers(client);
+ qemu_co_mutex_unlock(&client->send_lock);
+ return rc;
+}
+
+static ssize_t nbd_co_receive_request(NBDRequest *req, struct nbd_request *request)
+{
+ NBDClient *client = req->client;
+ uint32_t command;
+ ssize_t rc;
+
+ g_assert(qemu_in_coroutine());
+ client->recv_coroutine = qemu_coroutine_self();
+ nbd_update_can_read(client);
+
+ rc = nbd_receive_request(client->ioc, request);
+ if (rc < 0) {
+ if (rc != -EAGAIN) {
+ rc = -EIO;
+ }
+ goto out;
+ }
+
+ if ((request->from + request->len) < request->from) {
+ LOG("integer overflow detected! "
+ "you're probably being attacked");
+ rc = -EINVAL;
+ goto out;
+ }
+
+ TRACE("Decoding type");
+
+ command = request->type & NBD_CMD_MASK_COMMAND;
+ if (command == NBD_CMD_READ || command == NBD_CMD_WRITE) {
+ if (request->len > NBD_MAX_BUFFER_SIZE) {
+ LOG("len (%u) 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 (command == NBD_CMD_WRITE) {
+ TRACE("Reading %u byte(s)", request->len);
+
+ if (read_sync(client->ioc, req->data, request->len) != request->len) {
+ LOG("reading from socket failed");
+ rc = -EIO;
+ goto out;
+ }
+ }
+ rc = 0;
+
+out:
+ client->recv_coroutine = NULL;
+ nbd_update_can_read(client);
+
+ return rc;
+}
+
+static void nbd_trip(void *opaque)
+{
+ NBDClient *client = opaque;
+ NBDExport *exp = client->exp;
+ NBDRequest *req;
+ struct nbd_request request;
+ struct nbd_reply reply;
+ ssize_t ret;
+ uint32_t command;
+
+ TRACE("Reading request.");
+ if (client->closing) {
+ 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;
+ }
+ command = request.type & NBD_CMD_MASK_COMMAND;
+ if (command != NBD_CMD_DISC && (request.from + request.len) > exp->size) {
+ LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
+ ", Offset: %" PRIu64 "\n",
+ request.from, request.len,
+ (uint64_t)exp->size, (uint64_t)exp->dev_offset);
+ LOG("requested operation past EOF--bad client?");
+ goto invalid_request;
+ }
+
+ if (client->closing) {
+ /*
+ * The client may be closed when we are blocked in
+ * nbd_co_receive_request()
+ */
+ goto done;
+ }
+
+ switch (command) {
+ case NBD_CMD_READ:
+ TRACE("Request type is READ");
+
+ if (request.type & 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 %u 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");
+
+ ret = blk_pwrite(exp->blk, request.from + exp->dev_offset,
+ req->data, request.len);
+ if (ret < 0) {
+ LOG("writing to file failed");
+ reply.error = -ret;
+ goto error_reply;
+ }
+
+ if (request.type & NBD_CMD_FLAG_FUA) {
+ ret = blk_co_flush(exp->blk);
+ if (ret < 0) {
+ LOG("flush failed");
+ reply.error = -ret;
+ goto error_reply;
+ }
+ }
+
+ if (nbd_co_send_reply(req, &reply, 0) < 0) {
+ goto out;
+ }
+ break;
+ case NBD_CMD_DISC:
+ TRACE("Request type is DISCONNECT");
+ errno = 0;
+ goto out;
+ 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_discard(exp->blk, (request.from + exp->dev_offset)
+ / BDRV_SECTOR_SIZE,
+ request.len / BDRV_SECTOR_SIZE);
+ 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 (%u) received", request.type);
+ invalid_request:
+ reply.error = EINVAL;
+ error_reply:
+ if (nbd_co_send_reply(req, &reply, 0) < 0) {
+ goto out;
+ }
+ break;
+ }
+
+ TRACE("Request/Reply complete");
+
+done:
+ nbd_request_put(req);
+ return;
+
+out:
+ nbd_request_put(req);
+ client_close(client);
+}
+
+static void nbd_read(void *opaque)
+{
+ NBDClient *client = opaque;
+
+ if (client->recv_coroutine) {
+ qemu_coroutine_enter(client->recv_coroutine, NULL);
+ } else {
+ qemu_coroutine_enter(qemu_coroutine_create(nbd_trip), client);
+ }
+}
+
+static void nbd_restart_write(void *opaque)
+{
+ NBDClient *client = opaque;
+
+ qemu_coroutine_enter(client->send_coroutine, NULL);
+}
+
+static void nbd_set_handlers(NBDClient *client)
+{
+ if (client->exp && client->exp->ctx) {
+ aio_set_fd_handler(client->exp->ctx, client->sioc->fd,
+ true,
+ client->can_read ? nbd_read : NULL,
+ client->send_coroutine ? nbd_restart_write : NULL,
+ client);
+ }
+}
+
+static void nbd_unset_handlers(NBDClient *client)
+{
+ if (client->exp && client->exp->ctx) {
+ aio_set_fd_handler(client->exp->ctx, client->sioc->fd,
+ true, NULL, NULL, NULL);
+ }
+}
+
+static void nbd_update_can_read(NBDClient *client)
+{
+ bool can_read = client->recv_coroutine ||
+ client->nb_requests < MAX_NBD_REQUESTS;
+
+ if (can_read != client->can_read) {
+ client->can_read = can_read;
+ nbd_set_handlers(client);
+
+ /* There is no need to invoke aio_notify(), since aio_set_fd_handler()
+ * in nbd_set_handlers() will have taken care of that */
+ }
+}
+
+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);
+ nbd_set_handlers(client);
+
+ if (exp) {
+ QTAILQ_INSERT_TAIL(&exp->clients, client, next);
+ }
+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->can_read = true;
+ client->close = close_fn;
+
+ data->client = client;
+ data->co = qemu_coroutine_create(nbd_co_client_start);
+ qemu_coroutine_enter(data->co, data);
+}
Code Review / kvmfornfv.git / blobdiff