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-rw-r--r--nbd/server.c2745
1 files changed, 2745 insertions, 0 deletions
diff --git a/nbd/server.c b/nbd/server.c
new file mode 100644
index 000000000..4630dd732
--- /dev/null
+++ b/nbd/server.c
@@ -0,0 +1,2745 @@
+/*
+ * Copyright (C) 2016-2021 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 "block/export.h"
+#include "qapi/error.h"
+#include "qemu/queue.h"
+#include "trace.h"
+#include "nbd-internal.h"
+#include "qemu/units.h"
+
+#define NBD_META_ID_BASE_ALLOCATION 0
+#define NBD_META_ID_ALLOCATION_DEPTH 1
+/* Dirty bitmaps use 'NBD_META_ID_DIRTY_BITMAP + i', so keep this id last. */
+#define NBD_META_ID_DIRTY_BITMAP 2
+
+/*
+ * NBD_MAX_BLOCK_STATUS_EXTENTS: 1 MiB of extents data. An empirical
+ * constant. If an increase is needed, note that the NBD protocol
+ * recommends no larger than 32 mb, so that the client won't consider
+ * the reply as a denial of service attack.
+ */
+#define NBD_MAX_BLOCK_STATUS_EXTENTS (1 * MiB / 8)
+
+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 EOVERFLOW:
+ return NBD_EOVERFLOW;
+ case ENOTSUP:
+#if ENOTSUP != EOPNOTSUPP
+ case EOPNOTSUPP:
+#endif
+ return NBD_ENOTSUP;
+ 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 {
+ BlockExport common;
+
+ char *name;
+ char *description;
+ uint64_t size;
+ uint16_t nbdflags;
+ QTAILQ_HEAD(, NBDClient) clients;
+ QTAILQ_ENTRY(NBDExport) next;
+
+ BlockBackend *eject_notifier_blk;
+ Notifier eject_notifier;
+
+ bool allocation_depth;
+ BdrvDirtyBitmap **export_bitmaps;
+ size_t nr_export_bitmaps;
+};
+
+static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
+
+/* NBDExportMetaContexts represents a list of contexts to be exported,
+ * as selected by NBD_OPT_SET_META_CONTEXT. Also used for
+ * NBD_OPT_LIST_META_CONTEXT. */
+typedef struct NBDExportMetaContexts {
+ NBDExport *exp;
+ size_t count; /* number of negotiated contexts */
+ bool base_allocation; /* export base:allocation context (block status) */
+ bool allocation_depth; /* export qemu:allocation-depth */
+ bool *bitmaps; /*
+ * export qemu:dirty-bitmap:<export bitmap name>,
+ * sized by exp->nr_export_bitmaps
+ */
+} NBDExportMetaContexts;
+
+struct NBDClient {
+ int refcount;
+ void (*close_fn)(NBDClient *client, bool negotiated);
+
+ NBDExport *exp;
+ QCryptoTLSCreds *tlscreds;
+ char *tlsauthz;
+ 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 read_yielding;
+ bool quiescing;
+
+ QTAILQ_ENTRY(NBDClient) next;
+ int nb_requests;
+ bool closing;
+
+ uint32_t check_align; /* If non-zero, check for aligned client requests */
+
+ bool structured_reply;
+ NBDExportMetaContexts export_meta;
+
+ uint32_t opt; /* Current option being negotiated */
+ uint32_t optlen; /* remaining length of data in ioc for the option being
+ negotiated now */
+};
+
+static void nbd_client_receive_next_request(NBDClient *client);
+
+/* 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 inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option,
+ uint32_t type, uint32_t length)
+{
+ stq_be_p(&rep->magic, NBD_REP_MAGIC);
+ stl_be_p(&rep->option, option);
+ stl_be_p(&rep->type, type);
+ stl_be_p(&rep->length, length);
+}
+
+/* Send a reply header, including length, but no payload.
+ * Return -errno on error, 0 on success. */
+static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type,
+ uint32_t len, Error **errp)
+{
+ NBDOptionReply rep;
+
+ trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt),
+ type, nbd_rep_lookup(type), len);
+
+ assert(len < NBD_MAX_BUFFER_SIZE);
+
+ set_be_option_rep(&rep, client->opt, type, len);
+ return nbd_write(client->ioc, &rep, sizeof(rep), errp);
+}
+
+/* Send a reply header with default 0 length.
+ * Return -errno on error, 0 on success. */
+static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type,
+ Error **errp)
+{
+ return nbd_negotiate_send_rep_len(client, type, 0, errp);
+}
+
+/* Send an error reply.
+ * Return -errno on error, 0 on success. */
+static int GCC_FMT_ATTR(4, 0)
+nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,
+ Error **errp, const char *fmt, va_list va)
+{
+ ERRP_GUARD();
+ g_autofree char *msg = NULL;
+ int ret;
+ size_t len;
+
+ msg = g_strdup_vprintf(fmt, va);
+ len = strlen(msg);
+ assert(len < NBD_MAX_STRING_SIZE);
+ trace_nbd_negotiate_send_rep_err(msg);
+ ret = nbd_negotiate_send_rep_len(client, type, len, errp);
+ if (ret < 0) {
+ return ret;
+ }
+ if (nbd_write(client->ioc, msg, len, errp) < 0) {
+ error_prepend(errp, "write failed (error message): ");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+/*
+ * Return a malloc'd copy of @name suitable for use in an error reply.
+ */
+static char *
+nbd_sanitize_name(const char *name)
+{
+ if (strnlen(name, 80) < 80) {
+ return g_strdup(name);
+ }
+ /* XXX Should we also try to sanitize any control characters? */
+ return g_strdup_printf("%.80s...", name);
+}
+
+/* Send an error reply.
+ * Return -errno on error, 0 on success. */
+static int GCC_FMT_ATTR(4, 5)
+nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type,
+ Error **errp, const char *fmt, ...)
+{
+ va_list va;
+ int ret;
+
+ va_start(va, fmt);
+ ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
+ va_end(va);
+ return ret;
+}
+
+/* Drop remainder of the current option, and send a reply with the
+ * given error type and message. Return -errno on read or write
+ * failure; or 0 if connection is still live. */
+static int GCC_FMT_ATTR(4, 0)
+nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp,
+ const char *fmt, va_list va)
+{
+ int ret = nbd_drop(client->ioc, client->optlen, errp);
+
+ client->optlen = 0;
+ if (!ret) {
+ ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
+ }
+ return ret;
+}
+
+static int GCC_FMT_ATTR(4, 5)
+nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp,
+ const char *fmt, ...)
+{
+ int ret;
+ va_list va;
+
+ va_start(va, fmt);
+ ret = nbd_opt_vdrop(client, type, errp, fmt, va);
+ va_end(va);
+
+ return ret;
+}
+
+static int GCC_FMT_ATTR(3, 4)
+nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...)
+{
+ int ret;
+ va_list va;
+
+ va_start(va, fmt);
+ ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va);
+ va_end(va);
+
+ return ret;
+}
+
+/* Read size bytes from the unparsed payload of the current option.
+ * If @check_nul, require that no NUL bytes appear in buffer.
+ * Return -errno on I/O error, 0 if option was completely handled by
+ * sending a reply about inconsistent lengths, or 1 on success. */
+static int nbd_opt_read(NBDClient *client, void *buffer, size_t size,
+ bool check_nul, Error **errp)
+{
+ if (size > client->optlen) {
+ return nbd_opt_invalid(client, errp,
+ "Inconsistent lengths in option %s",
+ nbd_opt_lookup(client->opt));
+ }
+ client->optlen -= size;
+ if (qio_channel_read_all(client->ioc, buffer, size, errp) < 0) {
+ return -EIO;
+ }
+
+ if (check_nul && strnlen(buffer, size) != size) {
+ return nbd_opt_invalid(client, errp,
+ "Unexpected embedded NUL in option %s",
+ nbd_opt_lookup(client->opt));
+ }
+ return 1;
+}
+
+/* Drop size bytes from the unparsed payload of the current option.
+ * Return -errno on I/O error, 0 if option was completely handled by
+ * sending a reply about inconsistent lengths, or 1 on success. */
+static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp)
+{
+ if (size > client->optlen) {
+ return nbd_opt_invalid(client, errp,
+ "Inconsistent lengths in option %s",
+ nbd_opt_lookup(client->opt));
+ }
+ client->optlen -= size;
+ return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1;
+}
+
+/* nbd_opt_read_name
+ *
+ * Read a string with the format:
+ * uint32_t len (<= NBD_MAX_STRING_SIZE)
+ * len bytes string (not 0-terminated)
+ *
+ * On success, @name will be allocated.
+ * If @length is non-null, it will be set to the actual string length.
+ *
+ * Return -errno on I/O error, 0 if option was completely handled by
+ * sending a reply about inconsistent lengths, or 1 on success.
+ */
+static int nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length,
+ Error **errp)
+{
+ int ret;
+ uint32_t len;
+ g_autofree char *local_name = NULL;
+
+ *name = NULL;
+ ret = nbd_opt_read(client, &len, sizeof(len), false, errp);
+ if (ret <= 0) {
+ return ret;
+ }
+ len = cpu_to_be32(len);
+
+ if (len > NBD_MAX_STRING_SIZE) {
+ return nbd_opt_invalid(client, errp,
+ "Invalid name length: %" PRIu32, len);
+ }
+
+ local_name = g_malloc(len + 1);
+ ret = nbd_opt_read(client, local_name, len, true, errp);
+ if (ret <= 0) {
+ return ret;
+ }
+ local_name[len] = '\0';
+
+ if (length) {
+ *length = len;
+ }
+ *name = g_steal_pointer(&local_name);
+
+ return 1;
+}
+
+/* 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(NBDClient *client, NBDExport *exp,
+ Error **errp)
+{
+ ERRP_GUARD();
+ size_t name_len, desc_len;
+ uint32_t len;
+ const char *name = exp->name ? exp->name : "";
+ const char *desc = exp->description ? exp->description : "";
+ QIOChannel *ioc = client->ioc;
+ int ret;
+
+ trace_nbd_negotiate_send_rep_list(name, desc);
+ name_len = strlen(name);
+ desc_len = strlen(desc);
+ assert(name_len <= NBD_MAX_STRING_SIZE && desc_len <= NBD_MAX_STRING_SIZE);
+ len = name_len + desc_len + sizeof(len);
+ ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp);
+ if (ret < 0) {
+ return ret;
+ }
+
+ len = cpu_to_be32(name_len);
+ if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
+ error_prepend(errp, "write failed (name length): ");
+ return -EINVAL;
+ }
+
+ if (nbd_write(ioc, name, name_len, errp) < 0) {
+ error_prepend(errp, "write failed (name buffer): ");
+ return -EINVAL;
+ }
+
+ if (nbd_write(ioc, desc, desc_len, errp) < 0) {
+ error_prepend(errp, "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, Error **errp)
+{
+ NBDExport *exp;
+ assert(client->opt == NBD_OPT_LIST);
+
+ /* For each export, send a NBD_REP_SERVER reply. */
+ QTAILQ_FOREACH(exp, &exports, next) {
+ if (nbd_negotiate_send_rep_list(client, exp, errp)) {
+ return -EINVAL;
+ }
+ }
+ /* Finish with a NBD_REP_ACK. */
+ return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
+}
+
+static void nbd_check_meta_export(NBDClient *client)
+{
+ if (client->exp != client->export_meta.exp) {
+ client->export_meta.count = 0;
+ }
+}
+
+/* Send a reply to NBD_OPT_EXPORT_NAME.
+ * Return -errno on error, 0 on success. */
+static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes,
+ Error **errp)
+{
+ ERRP_GUARD();
+ g_autofree char *name = NULL;
+ char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
+ size_t len;
+ int ret;
+ uint16_t myflags;
+
+ /* Client sends:
+ [20 .. xx] export name (length bytes)
+ Server replies:
+ [ 0 .. 7] size
+ [ 8 .. 9] export flags
+ [10 .. 133] reserved (0) [unless no_zeroes]
+ */
+ trace_nbd_negotiate_handle_export_name();
+ if (client->optlen > NBD_MAX_STRING_SIZE) {
+ error_setg(errp, "Bad length received");
+ return -EINVAL;
+ }
+ name = g_malloc(client->optlen + 1);
+ if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) {
+ return -EIO;
+ }
+ name[client->optlen] = '\0';
+ client->optlen = 0;
+
+ trace_nbd_negotiate_handle_export_name_request(name);
+
+ client->exp = nbd_export_find(name);
+ if (!client->exp) {
+ error_setg(errp, "export not found");
+ return -EINVAL;
+ }
+
+ myflags = client->exp->nbdflags;
+ if (client->structured_reply) {
+ myflags |= NBD_FLAG_SEND_DF;
+ }
+ trace_nbd_negotiate_new_style_size_flags(client->exp->size, myflags);
+ stq_be_p(buf, client->exp->size);
+ stw_be_p(buf + 8, myflags);
+ len = no_zeroes ? 10 : sizeof(buf);
+ ret = nbd_write(client->ioc, buf, len, errp);
+ if (ret < 0) {
+ error_prepend(errp, "write failed: ");
+ return ret;
+ }
+
+ QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
+ blk_exp_ref(&client->exp->common);
+ nbd_check_meta_export(client);
+
+ return 0;
+}
+
+/* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
+ * The buffer does NOT include the info type prefix.
+ * Return -errno on error, 0 if ready to send more. */
+static int nbd_negotiate_send_info(NBDClient *client,
+ uint16_t info, uint32_t length, void *buf,
+ Error **errp)
+{
+ int rc;
+
+ trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);
+ rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO,
+ sizeof(info) + length, errp);
+ if (rc < 0) {
+ return rc;
+ }
+ info = cpu_to_be16(info);
+ if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) {
+ return -EIO;
+ }
+ if (nbd_write(client->ioc, buf, length, errp) < 0) {
+ return -EIO;
+ }
+ return 0;
+}
+
+/* nbd_reject_length: Handle any unexpected payload.
+ * @fatal requests that we quit talking to the client, even if we are able
+ * to successfully send an error reply.
+ * Return:
+ * -errno transmission error occurred or @fatal was requested, errp is set
+ * 0 error message successfully sent to client, errp is not set
+ */
+static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp)
+{
+ int ret;
+
+ assert(client->optlen);
+ ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length",
+ nbd_opt_lookup(client->opt));
+ if (fatal && !ret) {
+ error_setg(errp, "option '%s' has unexpected length",
+ nbd_opt_lookup(client->opt));
+ return -EINVAL;
+ }
+ return ret;
+}
+
+/* Handle NBD_OPT_INFO and NBD_OPT_GO.
+ * Return -errno on error, 0 if ready for next option, and 1 to move
+ * into transmission phase. */
+static int nbd_negotiate_handle_info(NBDClient *client, Error **errp)
+{
+ int rc;
+ g_autofree char *name = NULL;
+ NBDExport *exp;
+ uint16_t requests;
+ uint16_t request;
+ uint32_t namelen = 0;
+ bool sendname = false;
+ bool blocksize = false;
+ uint32_t sizes[3];
+ char buf[sizeof(uint64_t) + sizeof(uint16_t)];
+ uint32_t check_align = 0;
+ uint16_t myflags;
+
+ /* Client sends:
+ 4 bytes: L, name length (can be 0)
+ L bytes: export name
+ 2 bytes: N, number of requests (can be 0)
+ N * 2 bytes: N requests
+ */
+ rc = nbd_opt_read_name(client, &name, &namelen, errp);
+ if (rc <= 0) {
+ return rc;
+ }
+ trace_nbd_negotiate_handle_export_name_request(name);
+
+ rc = nbd_opt_read(client, &requests, sizeof(requests), false, errp);
+ if (rc <= 0) {
+ return rc;
+ }
+ requests = be16_to_cpu(requests);
+ trace_nbd_negotiate_handle_info_requests(requests);
+ while (requests--) {
+ rc = nbd_opt_read(client, &request, sizeof(request), false, errp);
+ if (rc <= 0) {
+ return rc;
+ }
+ request = be16_to_cpu(request);
+ trace_nbd_negotiate_handle_info_request(request,
+ nbd_info_lookup(request));
+ /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;
+ * everything else is either a request we don't know or
+ * something we send regardless of request */
+ switch (request) {
+ case NBD_INFO_NAME:
+ sendname = true;
+ break;
+ case NBD_INFO_BLOCK_SIZE:
+ blocksize = true;
+ break;
+ }
+ }
+ if (client->optlen) {
+ return nbd_reject_length(client, false, errp);
+ }
+
+ exp = nbd_export_find(name);
+ if (!exp) {
+ g_autofree char *sane_name = nbd_sanitize_name(name);
+
+ return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN,
+ errp, "export '%s' not present",
+ sane_name);
+ }
+
+ /* Don't bother sending NBD_INFO_NAME unless client requested it */
+ if (sendname) {
+ rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name,
+ errp);
+ if (rc < 0) {
+ return rc;
+ }
+ }
+
+ /* Send NBD_INFO_DESCRIPTION only if available, regardless of
+ * client request */
+ if (exp->description) {
+ size_t len = strlen(exp->description);
+
+ assert(len <= NBD_MAX_STRING_SIZE);
+ rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION,
+ len, exp->description, errp);
+ if (rc < 0) {
+ return rc;
+ }
+ }
+
+ /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size
+ * according to whether the client requested it, and according to
+ * whether this is OPT_INFO or OPT_GO. */
+ /* minimum - 1 for back-compat, or actual if client will obey it. */
+ if (client->opt == NBD_OPT_INFO || blocksize) {
+ check_align = sizes[0] = blk_get_request_alignment(exp->common.blk);
+ } else {
+ sizes[0] = 1;
+ }
+ assert(sizes[0] <= NBD_MAX_BUFFER_SIZE);
+ /* preferred - Hard-code to 4096 for now.
+ * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */
+ sizes[1] = MAX(4096, sizes[0]);
+ /* maximum - At most 32M, but smaller as appropriate. */
+ sizes[2] = MIN(blk_get_max_transfer(exp->common.blk), NBD_MAX_BUFFER_SIZE);
+ trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]);
+ sizes[0] = cpu_to_be32(sizes[0]);
+ sizes[1] = cpu_to_be32(sizes[1]);
+ sizes[2] = cpu_to_be32(sizes[2]);
+ rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE,
+ sizeof(sizes), sizes, errp);
+ if (rc < 0) {
+ return rc;
+ }
+
+ /* Send NBD_INFO_EXPORT always */
+ myflags = exp->nbdflags;
+ if (client->structured_reply) {
+ myflags |= NBD_FLAG_SEND_DF;
+ }
+ trace_nbd_negotiate_new_style_size_flags(exp->size, myflags);
+ stq_be_p(buf, exp->size);
+ stw_be_p(buf + 8, myflags);
+ rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT,
+ sizeof(buf), buf, errp);
+ if (rc < 0) {
+ return rc;
+ }
+
+ /*
+ * If the client is just asking for NBD_OPT_INFO, but forgot to
+ * request block sizes in a situation that would impact
+ * performance, then return an error. But for NBD_OPT_GO, we
+ * tolerate all clients, regardless of alignments.
+ */
+ if (client->opt == NBD_OPT_INFO && !blocksize &&
+ blk_get_request_alignment(exp->common.blk) > 1) {
+ return nbd_negotiate_send_rep_err(client,
+ NBD_REP_ERR_BLOCK_SIZE_REQD,
+ errp,
+ "request NBD_INFO_BLOCK_SIZE to "
+ "use this export");
+ }
+
+ /* Final reply */
+ rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
+ if (rc < 0) {
+ return rc;
+ }
+
+ if (client->opt == NBD_OPT_GO) {
+ client->exp = exp;
+ client->check_align = check_align;
+ QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
+ blk_exp_ref(&client->exp->common);
+ nbd_check_meta_export(client);
+ rc = 1;
+ }
+ 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,
+ Error **errp)
+{
+ QIOChannel *ioc;
+ QIOChannelTLS *tioc;
+ struct NBDTLSHandshakeData data = { 0 };
+
+ assert(client->opt == NBD_OPT_STARTTLS);
+
+ trace_nbd_negotiate_handle_starttls();
+ ioc = client->ioc;
+
+ if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) {
+ return NULL;
+ }
+
+ tioc = qio_channel_tls_new_server(ioc,
+ client->tlscreds,
+ client->tlsauthz,
+ errp);
+ if (!tioc) {
+ return NULL;
+ }
+
+ qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
+ trace_nbd_negotiate_handle_starttls_handshake();
+ data.loop = g_main_loop_new(g_main_context_default(), FALSE);
+ qio_channel_tls_handshake(tioc,
+ nbd_tls_handshake,
+ &data,
+ NULL,
+ NULL);
+
+ if (!data.complete) {
+ g_main_loop_run(data.loop);
+ }
+ g_main_loop_unref(data.loop);
+ if (data.error) {
+ object_unref(OBJECT(tioc));
+ error_propagate(errp, data.error);
+ return NULL;
+ }
+
+ return QIO_CHANNEL(tioc);
+}
+
+/* nbd_negotiate_send_meta_context
+ *
+ * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT
+ *
+ * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead.
+ */
+static int nbd_negotiate_send_meta_context(NBDClient *client,
+ const char *context,
+ uint32_t context_id,
+ Error **errp)
+{
+ NBDOptionReplyMetaContext opt;
+ struct iovec iov[] = {
+ {.iov_base = &opt, .iov_len = sizeof(opt)},
+ {.iov_base = (void *)context, .iov_len = strlen(context)}
+ };
+
+ assert(iov[1].iov_len <= NBD_MAX_STRING_SIZE);
+ if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
+ context_id = 0;
+ }
+
+ trace_nbd_negotiate_meta_query_reply(context, context_id);
+ set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT,
+ sizeof(opt) - sizeof(opt.h) + iov[1].iov_len);
+ stl_be_p(&opt.context_id, context_id);
+
+ return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0;
+}
+
+/*
+ * Return true if @query matches @pattern, or if @query is empty when
+ * the @client is performing _LIST_.
+ */
+static bool nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
+ const char *query)
+{
+ if (!*query) {
+ trace_nbd_negotiate_meta_query_parse("empty");
+ return client->opt == NBD_OPT_LIST_META_CONTEXT;
+ }
+ if (strcmp(query, pattern) == 0) {
+ trace_nbd_negotiate_meta_query_parse(pattern);
+ return true;
+ }
+ trace_nbd_negotiate_meta_query_skip("pattern not matched");
+ return false;
+}
+
+/*
+ * Return true and adjust @str in place if it begins with @prefix.
+ */
+static bool nbd_strshift(const char **str, const char *prefix)
+{
+ size_t len = strlen(prefix);
+
+ if (strncmp(*str, prefix, len) == 0) {
+ *str += len;
+ return true;
+ }
+ return false;
+}
+
+/* nbd_meta_base_query
+ *
+ * Handle queries to 'base' namespace. For now, only the base:allocation
+ * context is available. Return true if @query has been handled.
+ */
+static bool nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
+ const char *query)
+{
+ if (!nbd_strshift(&query, "base:")) {
+ return false;
+ }
+ trace_nbd_negotiate_meta_query_parse("base:");
+
+ if (nbd_meta_empty_or_pattern(client, "allocation", query)) {
+ meta->base_allocation = true;
+ }
+ return true;
+}
+
+/* nbd_meta_qemu_query
+ *
+ * Handle queries to 'qemu' namespace. For now, only the qemu:dirty-bitmap:
+ * and qemu:allocation-depth contexts are available. Return true if @query
+ * has been handled.
+ */
+static bool nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta,
+ const char *query)
+{
+ size_t i;
+
+ if (!nbd_strshift(&query, "qemu:")) {
+ return false;
+ }
+ trace_nbd_negotiate_meta_query_parse("qemu:");
+
+ if (!*query) {
+ if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
+ meta->allocation_depth = meta->exp->allocation_depth;
+ if (meta->exp->nr_export_bitmaps) {
+ memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps);
+ }
+ }
+ trace_nbd_negotiate_meta_query_parse("empty");
+ return true;
+ }
+
+ if (strcmp(query, "allocation-depth") == 0) {
+ trace_nbd_negotiate_meta_query_parse("allocation-depth");
+ meta->allocation_depth = meta->exp->allocation_depth;
+ return true;
+ }
+
+ if (nbd_strshift(&query, "dirty-bitmap:")) {
+ trace_nbd_negotiate_meta_query_parse("dirty-bitmap:");
+ if (!*query) {
+ if (client->opt == NBD_OPT_LIST_META_CONTEXT &&
+ meta->exp->nr_export_bitmaps) {
+ memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps);
+ }
+ trace_nbd_negotiate_meta_query_parse("empty");
+ return true;
+ }
+
+ for (i = 0; i < meta->exp->nr_export_bitmaps; i++) {
+ const char *bm_name;
+
+ bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]);
+ if (strcmp(bm_name, query) == 0) {
+ meta->bitmaps[i] = true;
+ trace_nbd_negotiate_meta_query_parse(query);
+ return true;
+ }
+ }
+ trace_nbd_negotiate_meta_query_skip("no dirty-bitmap match");
+ return true;
+ }
+
+ trace_nbd_negotiate_meta_query_skip("unknown qemu context");
+ return true;
+}
+
+/* nbd_negotiate_meta_query
+ *
+ * Parse namespace name and call corresponding function to parse body of the
+ * query.
+ *
+ * The only supported namespaces are 'base' and 'qemu'.
+ *
+ * Return -errno on I/O error, 0 if option was completely handled by
+ * sending a reply about inconsistent lengths, or 1 on success. */
+static int nbd_negotiate_meta_query(NBDClient *client,
+ NBDExportMetaContexts *meta, Error **errp)
+{
+ int ret;
+ g_autofree char *query = NULL;
+ uint32_t len;
+
+ ret = nbd_opt_read(client, &len, sizeof(len), false, errp);
+ if (ret <= 0) {
+ return ret;
+ }
+ len = cpu_to_be32(len);
+
+ if (len > NBD_MAX_STRING_SIZE) {
+ trace_nbd_negotiate_meta_query_skip("length too long");
+ return nbd_opt_skip(client, len, errp);
+ }
+
+ query = g_malloc(len + 1);
+ ret = nbd_opt_read(client, query, len, true, errp);
+ if (ret <= 0) {
+ return ret;
+ }
+ query[len] = '\0';
+
+ if (nbd_meta_base_query(client, meta, query)) {
+ return 1;
+ }
+ if (nbd_meta_qemu_query(client, meta, query)) {
+ return 1;
+ }
+
+ trace_nbd_negotiate_meta_query_skip("unknown namespace");
+ return 1;
+}
+
+/* nbd_negotiate_meta_queries
+ * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT
+ *
+ * Return -errno on I/O error, or 0 if option was completely handled. */
+static int nbd_negotiate_meta_queries(NBDClient *client,
+ NBDExportMetaContexts *meta, Error **errp)
+{
+ int ret;
+ g_autofree char *export_name = NULL;
+ /* Mark unused to work around https://bugs.llvm.org/show_bug.cgi?id=3888 */
+ g_autofree G_GNUC_UNUSED bool *bitmaps = NULL;
+ NBDExportMetaContexts local_meta = {0};
+ uint32_t nb_queries;
+ size_t i;
+ size_t count = 0;
+
+ if (client->opt == NBD_OPT_SET_META_CONTEXT && !client->structured_reply) {
+ return nbd_opt_invalid(client, errp,
+ "request option '%s' when structured reply "
+ "is not negotiated",
+ nbd_opt_lookup(client->opt));
+ }
+
+ if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
+ /* Only change the caller's meta on SET. */
+ meta = &local_meta;
+ }
+
+ g_free(meta->bitmaps);
+ memset(meta, 0, sizeof(*meta));
+
+ ret = nbd_opt_read_name(client, &export_name, NULL, errp);
+ if (ret <= 0) {
+ return ret;
+ }
+
+ meta->exp = nbd_export_find(export_name);
+ if (meta->exp == NULL) {
+ g_autofree char *sane_name = nbd_sanitize_name(export_name);
+
+ return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp,
+ "export '%s' not present", sane_name);
+ }
+ meta->bitmaps = g_new0(bool, meta->exp->nr_export_bitmaps);
+ if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
+ bitmaps = meta->bitmaps;
+ }
+
+ ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), false, errp);
+ if (ret <= 0) {
+ return ret;
+ }
+ nb_queries = cpu_to_be32(nb_queries);
+ trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt),
+ export_name, nb_queries);
+
+ if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) {
+ /* enable all known contexts */
+ meta->base_allocation = true;
+ meta->allocation_depth = meta->exp->allocation_depth;
+ if (meta->exp->nr_export_bitmaps) {
+ memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps);
+ }
+ } else {
+ for (i = 0; i < nb_queries; ++i) {
+ ret = nbd_negotiate_meta_query(client, meta, errp);
+ if (ret <= 0) {
+ return ret;
+ }
+ }
+ }
+
+ if (meta->base_allocation) {
+ ret = nbd_negotiate_send_meta_context(client, "base:allocation",
+ NBD_META_ID_BASE_ALLOCATION,
+ errp);
+ if (ret < 0) {
+ return ret;
+ }
+ count++;
+ }
+
+ if (meta->allocation_depth) {
+ ret = nbd_negotiate_send_meta_context(client, "qemu:allocation-depth",
+ NBD_META_ID_ALLOCATION_DEPTH,
+ errp);
+ if (ret < 0) {
+ return ret;
+ }
+ count++;
+ }
+
+ for (i = 0; i < meta->exp->nr_export_bitmaps; i++) {
+ const char *bm_name;
+ g_autofree char *context = NULL;
+
+ if (!meta->bitmaps[i]) {
+ continue;
+ }
+
+ bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]);
+ context = g_strdup_printf("qemu:dirty-bitmap:%s", bm_name);
+
+ ret = nbd_negotiate_send_meta_context(client, context,
+ NBD_META_ID_DIRTY_BITMAP + i,
+ errp);
+ if (ret < 0) {
+ return ret;
+ }
+ count++;
+ }
+
+ ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
+ if (ret == 0) {
+ meta->count = count;
+ }
+
+ return ret;
+}
+
+/* nbd_negotiate_options
+ * Process all NBD_OPT_* client option commands, during fixed newstyle
+ * negotiation.
+ * Return:
+ * -errno on error, errp is set
+ * 0 on successful negotiation, errp is not set
+ * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
+ * errp is not set
+ */
+static int nbd_negotiate_options(NBDClient *client, Error **errp)
+{
+ uint32_t flags;
+ bool fixedNewstyle = false;
+ bool no_zeroes = false;
+
+ /* Client sends:
+ [ 0 .. 3] client flags
+
+ Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO:
+ [ 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_read32(client->ioc, &flags, "flags", errp) < 0) {
+ return -EIO;
+ }
+ trace_nbd_negotiate_options_flags(flags);
+ if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
+ fixedNewstyle = true;
+ flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
+ }
+ if (flags & NBD_FLAG_C_NO_ZEROES) {
+ no_zeroes = true;
+ flags &= ~NBD_FLAG_C_NO_ZEROES;
+ }
+ if (flags != 0) {
+ error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);
+ return -EINVAL;
+ }
+
+ while (1) {
+ int ret;
+ uint32_t option, length;
+ uint64_t magic;
+
+ if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) {
+ return -EINVAL;
+ }
+ trace_nbd_negotiate_options_check_magic(magic);
+ if (magic != NBD_OPTS_MAGIC) {
+ error_setg(errp, "Bad magic received");
+ return -EINVAL;
+ }
+
+ if (nbd_read32(client->ioc, &option, "option", errp) < 0) {
+ return -EINVAL;
+ }
+ client->opt = option;
+
+ if (nbd_read32(client->ioc, &length, "option length", errp) < 0) {
+ return -EINVAL;
+ }
+ assert(!client->optlen);
+ client->optlen = length;
+
+ if (length > NBD_MAX_BUFFER_SIZE) {
+ error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
+ length, NBD_MAX_BUFFER_SIZE);
+ return -EINVAL;
+ }
+
+ trace_nbd_negotiate_options_check_option(option,
+ nbd_opt_lookup(option));
+ if (client->tlscreds &&
+ client->ioc == (QIOChannel *)client->sioc) {
+ QIOChannel *tioc;
+ if (!fixedNewstyle) {
+ error_setg(errp, "Unsupported option 0x%" PRIx32, option);
+ return -EINVAL;
+ }
+ switch (option) {
+ case NBD_OPT_STARTTLS:
+ if (length) {
+ /* Unconditionally drop the connection if the client
+ * can't start a TLS negotiation correctly */
+ return nbd_reject_length(client, true, errp);
+ }
+ tioc = nbd_negotiate_handle_starttls(client, errp);
+ if (!tioc) {
+ return -EIO;
+ }
+ ret = 0;
+ 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 */
+ error_setg(errp, "Option 0x%x not permitted before TLS",
+ option);
+ return -EINVAL;
+
+ default:
+ /* Let the client keep trying, unless they asked to
+ * quit. Always try to give an error back to the
+ * client; but when replying to OPT_ABORT, be aware
+ * that the client may hang up before receiving the
+ * error, in which case we are fine ignoring the
+ * resulting EPIPE. */
+ ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD,
+ option == NBD_OPT_ABORT ? NULL : errp,
+ "Option 0x%" PRIx32
+ " not permitted before TLS", option);
+ if (option == NBD_OPT_ABORT) {
+ return 1;
+ }
+ break;
+ }
+ } else if (fixedNewstyle) {
+ switch (option) {
+ case NBD_OPT_LIST:
+ if (length) {
+ ret = nbd_reject_length(client, false, errp);
+ } else {
+ ret = nbd_negotiate_handle_list(client, errp);
+ }
+ 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, NBD_REP_ACK, NULL);
+ return 1;
+
+ case NBD_OPT_EXPORT_NAME:
+ return nbd_negotiate_handle_export_name(client, no_zeroes,
+ errp);
+
+ case NBD_OPT_INFO:
+ case NBD_OPT_GO:
+ ret = nbd_negotiate_handle_info(client, errp);
+ if (ret == 1) {
+ assert(option == NBD_OPT_GO);
+ return 0;
+ }
+ break;
+
+ case NBD_OPT_STARTTLS:
+ if (length) {
+ ret = nbd_reject_length(client, false, errp);
+ } else if (client->tlscreds) {
+ ret = nbd_negotiate_send_rep_err(client,
+ NBD_REP_ERR_INVALID, errp,
+ "TLS already enabled");
+ } else {
+ ret = nbd_negotiate_send_rep_err(client,
+ NBD_REP_ERR_POLICY, errp,
+ "TLS not configured");
+ }
+ break;
+
+ case NBD_OPT_STRUCTURED_REPLY:
+ if (length) {
+ ret = nbd_reject_length(client, false, errp);
+ } else if (client->structured_reply) {
+ ret = nbd_negotiate_send_rep_err(
+ client, NBD_REP_ERR_INVALID, errp,
+ "structured reply already negotiated");
+ } else {
+ ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
+ client->structured_reply = true;
+ }
+ break;
+
+ case NBD_OPT_LIST_META_CONTEXT:
+ case NBD_OPT_SET_META_CONTEXT:
+ ret = nbd_negotiate_meta_queries(client, &client->export_meta,
+ errp);
+ break;
+
+ default:
+ ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp,
+ "Unsupported option %" PRIu32 " (%s)",
+ option, nbd_opt_lookup(option));
+ break;
+ }
+ } else {
+ /*
+ * If broken new-style we should drop the connection
+ * for anything except NBD_OPT_EXPORT_NAME
+ */
+ switch (option) {
+ case NBD_OPT_EXPORT_NAME:
+ return nbd_negotiate_handle_export_name(client, no_zeroes,
+ errp);
+
+ default:
+ error_setg(errp, "Unsupported option %" PRIu32 " (%s)",
+ option, nbd_opt_lookup(option));
+ return -EINVAL;
+ }
+ }
+ if (ret < 0) {
+ return ret;
+ }
+ }
+}
+
+/* nbd_negotiate
+ * Return:
+ * -errno on error, errp is set
+ * 0 on successful negotiation, errp is not set
+ * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
+ * errp is not set
+ */
+static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
+{
+ ERRP_GUARD();
+ char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";
+ int ret;
+
+ /* Old style negotiation header, no room for options
+ [ 0 .. 7] passwd ("NBDMAGIC")
+ [ 8 .. 15] magic (NBD_CLIENT_MAGIC)
+ [16 .. 23] size
+ [24 .. 27] export flags (zero-extended)
+ [28 .. 151] reserved (0)
+
+ New style negotiation header, client can send options
+ [ 0 .. 7] passwd ("NBDMAGIC")
+ [ 8 .. 15] magic (NBD_OPTS_MAGIC)
+ [16 .. 17] server flags (0)
+ ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO....
+ */
+
+ qio_channel_set_blocking(client->ioc, false, NULL);
+
+ trace_nbd_negotiate_begin();
+ memcpy(buf, "NBDMAGIC", 8);
+
+ stq_be_p(buf + 8, NBD_OPTS_MAGIC);
+ stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);
+
+ if (nbd_write(client->ioc, buf, 18, errp) < 0) {
+ error_prepend(errp, "write failed: ");
+ return -EINVAL;
+ }
+ ret = nbd_negotiate_options(client, errp);
+ if (ret != 0) {
+ if (ret < 0) {
+ error_prepend(errp, "option negotiation failed: ");
+ }
+ return ret;
+ }
+
+ /* Attach the channel to the same AioContext as the export */
+ if (client->exp && client->exp->common.ctx) {
+ qio_channel_attach_aio_context(client->ioc, client->exp->common.ctx);
+ }
+
+ assert(!client->optlen);
+ trace_nbd_negotiate_success();
+
+ return 0;
+}
+
+/* nbd_read_eof
+ * Tries to read @size bytes from @ioc. This is a local implementation of
+ * qio_channel_readv_all_eof. We have it here because we need it to be
+ * interruptible and to know when the coroutine is yielding.
+ * Returns 1 on success
+ * 0 on eof, when no data was read (errp is not set)
+ * negative errno on failure (errp is set)
+ */
+static inline int coroutine_fn
+nbd_read_eof(NBDClient *client, void *buffer, size_t size, Error **errp)
+{
+ bool partial = false;
+
+ assert(size);
+ while (size > 0) {
+ struct iovec iov = { .iov_base = buffer, .iov_len = size };
+ ssize_t len;
+
+ len = qio_channel_readv(client->ioc, &iov, 1, errp);
+ if (len == QIO_CHANNEL_ERR_BLOCK) {
+ client->read_yielding = true;
+ qio_channel_yield(client->ioc, G_IO_IN);
+ client->read_yielding = false;
+ if (client->quiescing) {
+ return -EAGAIN;
+ }
+ continue;
+ } else if (len < 0) {
+ return -EIO;
+ } else if (len == 0) {
+ if (partial) {
+ error_setg(errp,
+ "Unexpected end-of-file before all bytes were read");
+ return -EIO;
+ } else {
+ return 0;
+ }
+ }
+
+ partial = true;
+ size -= len;
+ buffer = (uint8_t *) buffer + len;
+ }
+ return 1;
+}
+
+static int nbd_receive_request(NBDClient *client, NBDRequest *request,
+ Error **errp)
+{
+ uint8_t buf[NBD_REQUEST_SIZE];
+ uint32_t magic;
+ int ret;
+
+ ret = nbd_read_eof(client, buf, sizeof(buf), errp);
+ if (ret < 0) {
+ return ret;
+ }
+ if (ret == 0) {
+ return -EIO;
+ }
+
+ /* 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_nbd_receive_request(magic, request->flags, request->type,
+ request->from, request->len);
+
+ if (magic != NBD_REQUEST_MAGIC) {
+ error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic);
+ 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->tlsauthz);
+ if (client->exp) {
+ QTAILQ_REMOVE(&client->exp->clients, client, next);
+ blk_exp_unref(&client->exp->common);
+ }
+ g_free(client->export_meta.bitmaps);
+ g_free(client);
+ }
+}
+
+static void client_close(NBDClient *client, bool negotiated)
+{
+ 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_fn) {
+ client->close_fn(client, negotiated);
+ }
+}
+
+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--;
+
+ if (client->quiescing && client->nb_requests == 0) {
+ aio_wait_kick();
+ }
+
+ 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_nbd_blk_aio_attached(exp->name, ctx);
+
+ exp->common.ctx = ctx;
+
+ QTAILQ_FOREACH(client, &exp->clients, next) {
+ qio_channel_attach_aio_context(client->ioc, ctx);
+
+ assert(client->nb_requests == 0);
+ assert(client->recv_coroutine == NULL);
+ assert(client->send_coroutine == NULL);
+ }
+}
+
+static void blk_aio_detach(void *opaque)
+{
+ NBDExport *exp = opaque;
+ NBDClient *client;
+
+ trace_nbd_blk_aio_detach(exp->name, exp->common.ctx);
+
+ QTAILQ_FOREACH(client, &exp->clients, next) {
+ qio_channel_detach_aio_context(client->ioc);
+ }
+
+ exp->common.ctx = NULL;
+}
+
+static void nbd_drained_begin(void *opaque)
+{
+ NBDExport *exp = opaque;
+ NBDClient *client;
+
+ QTAILQ_FOREACH(client, &exp->clients, next) {
+ client->quiescing = true;
+ }
+}
+
+static void nbd_drained_end(void *opaque)
+{
+ NBDExport *exp = opaque;
+ NBDClient *client;
+
+ QTAILQ_FOREACH(client, &exp->clients, next) {
+ client->quiescing = false;
+ nbd_client_receive_next_request(client);
+ }
+}
+
+static bool nbd_drained_poll(void *opaque)
+{
+ NBDExport *exp = opaque;
+ NBDClient *client;
+
+ QTAILQ_FOREACH(client, &exp->clients, next) {
+ if (client->nb_requests != 0) {
+ /*
+ * If there's a coroutine waiting for a request on nbd_read_eof()
+ * enter it here so we don't depend on the client to wake it up.
+ */
+ if (client->recv_coroutine != NULL && client->read_yielding) {
+ qemu_aio_coroutine_enter(exp->common.ctx,
+ client->recv_coroutine);
+ }
+
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static void nbd_eject_notifier(Notifier *n, void *data)
+{
+ NBDExport *exp = container_of(n, NBDExport, eject_notifier);
+
+ blk_exp_request_shutdown(&exp->common);
+}
+
+void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk)
+{
+ NBDExport *nbd_exp = container_of(exp, NBDExport, common);
+ assert(exp->drv == &blk_exp_nbd);
+ assert(nbd_exp->eject_notifier_blk == NULL);
+
+ blk_ref(blk);
+ nbd_exp->eject_notifier_blk = blk;
+ nbd_exp->eject_notifier.notify = nbd_eject_notifier;
+ blk_add_remove_bs_notifier(blk, &nbd_exp->eject_notifier);
+}
+
+static const BlockDevOps nbd_block_ops = {
+ .drained_begin = nbd_drained_begin,
+ .drained_end = nbd_drained_end,
+ .drained_poll = nbd_drained_poll,
+};
+
+static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args,
+ Error **errp)
+{
+ NBDExport *exp = container_of(blk_exp, NBDExport, common);
+ BlockExportOptionsNbd *arg = &exp_args->u.nbd;
+ BlockBackend *blk = blk_exp->blk;
+ int64_t size;
+ uint64_t perm, shared_perm;
+ bool readonly = !exp_args->writable;
+ bool shared = !exp_args->writable;
+ strList *bitmaps;
+ size_t i;
+ int ret;
+
+ assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD);
+
+ if (!nbd_server_is_running()) {
+ error_setg(errp, "NBD server not running");
+ return -EINVAL;
+ }
+
+ if (!arg->has_name) {
+ arg->name = exp_args->node_name;
+ }
+
+ if (strlen(arg->name) > NBD_MAX_STRING_SIZE) {
+ error_setg(errp, "export name '%s' too long", arg->name);
+ return -EINVAL;
+ }
+
+ if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) {
+ error_setg(errp, "description '%s' too long", arg->description);
+ return -EINVAL;
+ }
+
+ if (nbd_export_find(arg->name)) {
+ error_setg(errp, "NBD server already has export named '%s'", arg->name);
+ return -EEXIST;
+ }
+
+ size = blk_getlength(blk);
+ if (size < 0) {
+ error_setg_errno(errp, -size,
+ "Failed to determine the NBD export's length");
+ return size;
+ }
+
+ /* Don't allow resize while the NBD server is running, otherwise we don't
+ * care what happens with the node. */
+ blk_get_perm(blk, &perm, &shared_perm);
+ ret = blk_set_perm(blk, perm, shared_perm & ~BLK_PERM_RESIZE, errp);
+ if (ret < 0) {
+ return ret;
+ }
+
+ QTAILQ_INIT(&exp->clients);
+ exp->name = g_strdup(arg->name);
+ exp->description = g_strdup(arg->description);
+ exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH |
+ NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE);
+ if (readonly) {
+ exp->nbdflags |= NBD_FLAG_READ_ONLY;
+ if (shared) {
+ exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN;
+ }
+ } else {
+ exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES |
+ NBD_FLAG_SEND_FAST_ZERO);
+ }
+ exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE);
+
+ for (bitmaps = arg->bitmaps; bitmaps; bitmaps = bitmaps->next) {
+ exp->nr_export_bitmaps++;
+ }
+ exp->export_bitmaps = g_new0(BdrvDirtyBitmap *, exp->nr_export_bitmaps);
+ for (i = 0, bitmaps = arg->bitmaps; bitmaps;
+ i++, bitmaps = bitmaps->next) {
+ const char *bitmap = bitmaps->value;
+ BlockDriverState *bs = blk_bs(blk);
+ BdrvDirtyBitmap *bm = NULL;
+
+ while (bs) {
+ bm = bdrv_find_dirty_bitmap(bs, bitmap);
+ if (bm != NULL) {
+ break;
+ }
+
+ bs = bdrv_filter_or_cow_bs(bs);
+ }
+
+ if (bm == NULL) {
+ ret = -ENOENT;
+ error_setg(errp, "Bitmap '%s' is not found", bitmap);
+ goto fail;
+ }
+
+ if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ if (readonly && bdrv_is_writable(bs) &&
+ bdrv_dirty_bitmap_enabled(bm)) {
+ ret = -EINVAL;
+ error_setg(errp,
+ "Enabled bitmap '%s' incompatible with readonly export",
+ bitmap);
+ goto fail;
+ }
+
+ exp->export_bitmaps[i] = bm;
+ assert(strlen(bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE);
+ }
+
+ /* Mark bitmaps busy in a separate loop, to simplify roll-back concerns. */
+ for (i = 0; i < exp->nr_export_bitmaps; i++) {
+ bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], true);
+ }
+
+ exp->allocation_depth = arg->allocation_depth;
+
+ /*
+ * We need to inhibit request queuing in the block layer to ensure we can
+ * be properly quiesced when entering a drained section, as our coroutines
+ * servicing pending requests might enter blk_pread().
+ */
+ blk_set_disable_request_queuing(blk, true);
+
+ blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
+
+ blk_set_dev_ops(blk, &nbd_block_ops, exp);
+
+ QTAILQ_INSERT_TAIL(&exports, exp, next);
+
+ return 0;
+
+fail:
+ g_free(exp->export_bitmaps);
+ g_free(exp->name);
+ g_free(exp->description);
+ return ret;
+}
+
+NBDExport *nbd_export_find(const char *name)
+{
+ NBDExport *exp;
+ QTAILQ_FOREACH(exp, &exports, next) {
+ if (strcmp(name, exp->name) == 0) {
+ return exp;
+ }
+ }
+
+ return NULL;
+}
+
+AioContext *
+nbd_export_aio_context(NBDExport *exp)
+{
+ return exp->common.ctx;
+}
+
+static void nbd_export_request_shutdown(BlockExport *blk_exp)
+{
+ NBDExport *exp = container_of(blk_exp, NBDExport, common);
+ NBDClient *client, *next;
+
+ blk_exp_ref(&exp->common);
+ /*
+ * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a
+ * close mode that stops advertising the export to new clients but
+ * still permits existing clients to run to completion? Because of
+ * that possibility, nbd_export_close() can be called more than
+ * once on an export.
+ */
+ QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
+ client_close(client, true);
+ }
+ if (exp->name) {
+ g_free(exp->name);
+ exp->name = NULL;
+ QTAILQ_REMOVE(&exports, exp, next);
+ }
+ blk_exp_unref(&exp->common);
+}
+
+static void nbd_export_delete(BlockExport *blk_exp)
+{
+ size_t i;
+ NBDExport *exp = container_of(blk_exp, NBDExport, common);
+
+ assert(exp->name == NULL);
+ assert(QTAILQ_EMPTY(&exp->clients));
+
+ g_free(exp->description);
+ exp->description = NULL;
+
+ if (exp->common.blk) {
+ if (exp->eject_notifier_blk) {
+ notifier_remove(&exp->eject_notifier);
+ blk_unref(exp->eject_notifier_blk);
+ }
+ blk_remove_aio_context_notifier(exp->common.blk, blk_aio_attached,
+ blk_aio_detach, exp);
+ blk_set_disable_request_queuing(exp->common.blk, false);
+ }
+
+ for (i = 0; i < exp->nr_export_bitmaps; i++) {
+ bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], false);
+ }
+}
+
+const BlockExportDriver blk_exp_nbd = {
+ .type = BLOCK_EXPORT_TYPE_NBD,
+ .instance_size = sizeof(NBDExport),
+ .create = nbd_export_create,
+ .delete = nbd_export_delete,
+ .request_shutdown = nbd_export_request_shutdown,
+};
+
+static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov,
+ unsigned niov, Error **errp)
+{
+ int ret;
+
+ g_assert(qemu_in_coroutine());
+ qemu_co_mutex_lock(&client->send_lock);
+ client->send_coroutine = qemu_coroutine_self();
+
+ ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0;
+
+ client->send_coroutine = NULL;
+ qemu_co_mutex_unlock(&client->send_lock);
+
+ return ret;
+}
+
+static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,
+ uint64_t handle)
+{
+ stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);
+ stl_be_p(&reply->error, error);
+ stq_be_p(&reply->handle, handle);
+}
+
+static int nbd_co_send_simple_reply(NBDClient *client,
+ uint64_t handle,
+ uint32_t error,
+ void *data,
+ size_t len,
+ Error **errp)
+{
+ NBDSimpleReply reply;
+ int nbd_err = system_errno_to_nbd_errno(error);
+ struct iovec iov[] = {
+ {.iov_base = &reply, .iov_len = sizeof(reply)},
+ {.iov_base = data, .iov_len = len}
+ };
+
+ trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err),
+ len);
+ set_be_simple_reply(&reply, nbd_err, handle);
+
+ return nbd_co_send_iov(client, iov, len ? 2 : 1, errp);
+}
+
+static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags,
+ uint16_t type, uint64_t handle, uint32_t length)
+{
+ stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC);
+ stw_be_p(&chunk->flags, flags);
+ stw_be_p(&chunk->type, type);
+ stq_be_p(&chunk->handle, handle);
+ stl_be_p(&chunk->length, length);
+}
+
+static int coroutine_fn nbd_co_send_structured_done(NBDClient *client,
+ uint64_t handle,
+ Error **errp)
+{
+ NBDStructuredReplyChunk chunk;
+ struct iovec iov[] = {
+ {.iov_base = &chunk, .iov_len = sizeof(chunk)},
+ };
+
+ trace_nbd_co_send_structured_done(handle);
+ set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0);
+
+ return nbd_co_send_iov(client, iov, 1, errp);
+}
+
+static int coroutine_fn nbd_co_send_structured_read(NBDClient *client,
+ uint64_t handle,
+ uint64_t offset,
+ void *data,
+ size_t size,
+ bool final,
+ Error **errp)
+{
+ NBDStructuredReadData chunk;
+ struct iovec iov[] = {
+ {.iov_base = &chunk, .iov_len = sizeof(chunk)},
+ {.iov_base = data, .iov_len = size}
+ };
+
+ assert(size);
+ trace_nbd_co_send_structured_read(handle, offset, data, size);
+ set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
+ NBD_REPLY_TYPE_OFFSET_DATA, handle,
+ sizeof(chunk) - sizeof(chunk.h) + size);
+ stq_be_p(&chunk.offset, offset);
+
+ return nbd_co_send_iov(client, iov, 2, errp);
+}
+
+static int coroutine_fn nbd_co_send_structured_error(NBDClient *client,
+ uint64_t handle,
+ uint32_t error,
+ const char *msg,
+ Error **errp)
+{
+ NBDStructuredError chunk;
+ int nbd_err = system_errno_to_nbd_errno(error);
+ struct iovec iov[] = {
+ {.iov_base = &chunk, .iov_len = sizeof(chunk)},
+ {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0},
+ };
+
+ assert(nbd_err);
+ trace_nbd_co_send_structured_error(handle, nbd_err,
+ nbd_err_lookup(nbd_err), msg ? msg : "");
+ set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle,
+ sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
+ stl_be_p(&chunk.error, nbd_err);
+ stw_be_p(&chunk.message_length, iov[1].iov_len);
+
+ return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp);
+}
+
+/* Do a sparse read and send the structured reply to the client.
+ * Returns -errno if sending fails. bdrv_block_status_above() failure is
+ * reported to the client, at which point this function succeeds.
+ */
+static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
+ uint64_t handle,
+ uint64_t offset,
+ uint8_t *data,
+ size_t size,
+ Error **errp)
+{
+ int ret = 0;
+ NBDExport *exp = client->exp;
+ size_t progress = 0;
+
+ while (progress < size) {
+ int64_t pnum;
+ int status = bdrv_block_status_above(blk_bs(exp->common.blk), NULL,
+ offset + progress,
+ size - progress, &pnum, NULL,
+ NULL);
+ bool final;
+
+ if (status < 0) {
+ char *msg = g_strdup_printf("unable to check for holes: %s",
+ strerror(-status));
+
+ ret = nbd_co_send_structured_error(client, handle, -status, msg,
+ errp);
+ g_free(msg);
+ return ret;
+ }
+ assert(pnum && pnum <= size - progress);
+ final = progress + pnum == size;
+ if (status & BDRV_BLOCK_ZERO) {
+ NBDStructuredReadHole chunk;
+ struct iovec iov[] = {
+ {.iov_base = &chunk, .iov_len = sizeof(chunk)},
+ };
+
+ trace_nbd_co_send_structured_read_hole(handle, offset + progress,
+ pnum);
+ set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
+ NBD_REPLY_TYPE_OFFSET_HOLE,
+ handle, sizeof(chunk) - sizeof(chunk.h));
+ stq_be_p(&chunk.offset, offset + progress);
+ stl_be_p(&chunk.length, pnum);
+ ret = nbd_co_send_iov(client, iov, 1, errp);
+ } else {
+ ret = blk_pread(exp->common.blk, offset + progress,
+ data + progress, pnum);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "reading from file failed");
+ break;
+ }
+ ret = nbd_co_send_structured_read(client, handle, offset + progress,
+ data + progress, pnum, final,
+ errp);
+ }
+
+ if (ret < 0) {
+ break;
+ }
+ progress += pnum;
+ }
+ return ret;
+}
+
+typedef struct NBDExtentArray {
+ NBDExtent *extents;
+ unsigned int nb_alloc;
+ unsigned int count;
+ uint64_t total_length;
+ bool can_add;
+ bool converted_to_be;
+} NBDExtentArray;
+
+static NBDExtentArray *nbd_extent_array_new(unsigned int nb_alloc)
+{
+ NBDExtentArray *ea = g_new0(NBDExtentArray, 1);
+
+ ea->nb_alloc = nb_alloc;
+ ea->extents = g_new(NBDExtent, nb_alloc);
+ ea->can_add = true;
+
+ return ea;
+}
+
+static void nbd_extent_array_free(NBDExtentArray *ea)
+{
+ g_free(ea->extents);
+ g_free(ea);
+}
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray, nbd_extent_array_free);
+
+/* Further modifications of the array after conversion are abandoned */
+static void nbd_extent_array_convert_to_be(NBDExtentArray *ea)
+{
+ int i;
+
+ assert(!ea->converted_to_be);
+ ea->can_add = false;
+ ea->converted_to_be = true;
+
+ for (i = 0; i < ea->count; i++) {
+ ea->extents[i].flags = cpu_to_be32(ea->extents[i].flags);
+ ea->extents[i].length = cpu_to_be32(ea->extents[i].length);
+ }
+}
+
+/*
+ * Add extent to NBDExtentArray. If extent can't be added (no available space),
+ * return -1.
+ * For safety, when returning -1 for the first time, .can_add is set to false,
+ * further call to nbd_extent_array_add() will crash.
+ * (to avoid the situation, when after failing to add an extent (returned -1),
+ * user miss this failure and add another extent, which is successfully added
+ * (array is full, but new extent may be squashed into the last one), then we
+ * have invalid array with skipped extent)
+ */
+static int nbd_extent_array_add(NBDExtentArray *ea,
+ uint32_t length, uint32_t flags)
+{
+ assert(ea->can_add);
+
+ if (!length) {
+ return 0;
+ }
+
+ /* Extend previous extent if flags are the same */
+ if (ea->count > 0 && flags == ea->extents[ea->count - 1].flags) {
+ uint64_t sum = (uint64_t)length + ea->extents[ea->count - 1].length;
+
+ if (sum <= UINT32_MAX) {
+ ea->extents[ea->count - 1].length = sum;
+ ea->total_length += length;
+ return 0;
+ }
+ }
+
+ if (ea->count >= ea->nb_alloc) {
+ ea->can_add = false;
+ return -1;
+ }
+
+ ea->total_length += length;
+ ea->extents[ea->count] = (NBDExtent) {.length = length, .flags = flags};
+ ea->count++;
+
+ return 0;
+}
+
+static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset,
+ uint64_t bytes, NBDExtentArray *ea)
+{
+ while (bytes) {
+ uint32_t flags;
+ int64_t num;
+ int ret = bdrv_block_status_above(bs, NULL, offset, bytes, &num,
+ NULL, NULL);
+
+ if (ret < 0) {
+ return ret;
+ }
+
+ flags = (ret & BDRV_BLOCK_DATA ? 0 : NBD_STATE_HOLE) |
+ (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0);
+
+ if (nbd_extent_array_add(ea, num, flags) < 0) {
+ return 0;
+ }
+
+ offset += num;
+ bytes -= num;
+ }
+
+ return 0;
+}
+
+static int blockalloc_to_extents(BlockDriverState *bs, uint64_t offset,
+ uint64_t bytes, NBDExtentArray *ea)
+{
+ while (bytes) {
+ int64_t num;
+ int ret = bdrv_is_allocated_above(bs, NULL, false, offset, bytes,
+ &num);
+
+ if (ret < 0) {
+ return ret;
+ }
+
+ if (nbd_extent_array_add(ea, num, ret) < 0) {
+ return 0;
+ }
+
+ offset += num;
+ bytes -= num;
+ }
+
+ return 0;
+}
+
+/*
+ * nbd_co_send_extents
+ *
+ * @ea is converted to BE by the function
+ * @last controls whether NBD_REPLY_FLAG_DONE is sent.
+ */
+static int nbd_co_send_extents(NBDClient *client, uint64_t handle,
+ NBDExtentArray *ea,
+ bool last, uint32_t context_id, Error **errp)
+{
+ NBDStructuredMeta chunk;
+ struct iovec iov[] = {
+ {.iov_base = &chunk, .iov_len = sizeof(chunk)},
+ {.iov_base = ea->extents, .iov_len = ea->count * sizeof(ea->extents[0])}
+ };
+
+ nbd_extent_array_convert_to_be(ea);
+
+ trace_nbd_co_send_extents(handle, ea->count, context_id, ea->total_length,
+ last);
+ set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0,
+ NBD_REPLY_TYPE_BLOCK_STATUS,
+ handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
+ stl_be_p(&chunk.context_id, context_id);
+
+ return nbd_co_send_iov(client, iov, 2, errp);
+}
+
+/* Get block status from the exported device and send it to the client */
+static int nbd_co_send_block_status(NBDClient *client, uint64_t handle,
+ BlockDriverState *bs, uint64_t offset,
+ uint32_t length, bool dont_fragment,
+ bool last, uint32_t context_id,
+ Error **errp)
+{
+ int ret;
+ unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS;
+ g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents);
+
+ if (context_id == NBD_META_ID_BASE_ALLOCATION) {
+ ret = blockstatus_to_extents(bs, offset, length, ea);
+ } else {
+ ret = blockalloc_to_extents(bs, offset, length, ea);
+ }
+ if (ret < 0) {
+ return nbd_co_send_structured_error(
+ client, handle, -ret, "can't get block status", errp);
+ }
+
+ return nbd_co_send_extents(client, handle, ea, last, context_id, errp);
+}
+
+/* Populate @ea from a dirty bitmap. */
+static void bitmap_to_extents(BdrvDirtyBitmap *bitmap,
+ uint64_t offset, uint64_t length,
+ NBDExtentArray *es)
+{
+ int64_t start, dirty_start, dirty_count;
+ int64_t end = offset + length;
+ bool full = false;
+
+ bdrv_dirty_bitmap_lock(bitmap);
+
+ for (start = offset;
+ bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, INT32_MAX,
+ &dirty_start, &dirty_count);
+ start = dirty_start + dirty_count)
+ {
+ if ((nbd_extent_array_add(es, dirty_start - start, 0) < 0) ||
+ (nbd_extent_array_add(es, dirty_count, NBD_STATE_DIRTY) < 0))
+ {
+ full = true;
+ break;
+ }
+ }
+
+ if (!full) {
+ /* last non dirty extent, nothing to do if array is now full */
+ (void) nbd_extent_array_add(es, end - start, 0);
+ }
+
+ bdrv_dirty_bitmap_unlock(bitmap);
+}
+
+static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle,
+ BdrvDirtyBitmap *bitmap, uint64_t offset,
+ uint32_t length, bool dont_fragment, bool last,
+ uint32_t context_id, Error **errp)
+{
+ unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS;
+ g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents);
+
+ bitmap_to_extents(bitmap, offset, length, ea);
+
+ return nbd_co_send_extents(client, handle, ea, last, context_id, errp);
+}
+
+/* nbd_co_receive_request
+ * Collect a client request. Return 0 if request looks valid, -EIO to drop
+ * connection right away, -EAGAIN to indicate we were interrupted and the
+ * channel should be quiesced, 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 int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,
+ Error **errp)
+{
+ NBDClient *client = req->client;
+ int valid_flags;
+ int ret;
+
+ g_assert(qemu_in_coroutine());
+ assert(client->recv_coroutine == qemu_coroutine_self());
+ ret = nbd_receive_request(client, request, errp);
+ if (ret < 0) {
+ return ret;
+ }
+
+ trace_nbd_co_receive_request_decode_type(request->handle, request->type,
+ nbd_cmd_lookup(request->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 */
+ return -EIO;
+ }
+
+ if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE ||
+ request->type == NBD_CMD_CACHE)
+ {
+ if (request->len > NBD_MAX_BUFFER_SIZE) {
+ error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
+ request->len, NBD_MAX_BUFFER_SIZE);
+ return -EINVAL;
+ }
+
+ if (request->type != NBD_CMD_CACHE) {
+ req->data = blk_try_blockalign(client->exp->common.blk,
+ request->len);
+ if (req->data == NULL) {
+ error_setg(errp, "No memory");
+ return -ENOMEM;
+ }
+ }
+ }
+
+ if (request->type == NBD_CMD_WRITE) {
+ if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data",
+ errp) < 0)
+ {
+ return -EIO;
+ }
+ req->complete = true;
+
+ trace_nbd_co_receive_request_payload_received(request->handle,
+ request->len);
+ }
+
+ /* Sanity checks. */
+ if (client->exp->nbdflags & NBD_FLAG_READ_ONLY &&
+ (request->type == NBD_CMD_WRITE ||
+ request->type == NBD_CMD_WRITE_ZEROES ||
+ request->type == NBD_CMD_TRIM)) {
+ error_setg(errp, "Export is read-only");
+ return -EROFS;
+ }
+ if (request->from > client->exp->size ||
+ request->len > client->exp->size - request->from) {
+ error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32
+ ", Size: %" PRIu64, request->from, request->len,
+ client->exp->size);
+ return (request->type == NBD_CMD_WRITE ||
+ request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL;
+ }
+ if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len,
+ client->check_align)) {
+ /*
+ * The block layer gracefully handles unaligned requests, but
+ * it's still worth tracing client non-compliance
+ */
+ trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type),
+ request->from,
+ request->len,
+ client->check_align);
+ }
+ valid_flags = NBD_CMD_FLAG_FUA;
+ if (request->type == NBD_CMD_READ && client->structured_reply) {
+ valid_flags |= NBD_CMD_FLAG_DF;
+ } else if (request->type == NBD_CMD_WRITE_ZEROES) {
+ valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO;
+ } else if (request->type == NBD_CMD_BLOCK_STATUS) {
+ valid_flags |= NBD_CMD_FLAG_REQ_ONE;
+ }
+ if (request->flags & ~valid_flags) {
+ error_setg(errp, "unsupported flags for command %s (got 0x%x)",
+ nbd_cmd_lookup(request->type), request->flags);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/* Send simple reply without a payload, or a structured error
+ * @error_msg is ignored if @ret >= 0
+ * Returns 0 if connection is still live, -errno on failure to talk to client
+ */
+static coroutine_fn int nbd_send_generic_reply(NBDClient *client,
+ uint64_t handle,
+ int ret,
+ const char *error_msg,
+ Error **errp)
+{
+ if (client->structured_reply && ret < 0) {
+ return nbd_co_send_structured_error(client, handle, -ret, error_msg,
+ errp);
+ } else {
+ return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0,
+ NULL, 0, errp);
+ }
+}
+
+/* Handle NBD_CMD_READ request.
+ * Return -errno if sending fails. Other errors are reported directly to the
+ * client as an error reply. */
+static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request,
+ uint8_t *data, Error **errp)
+{
+ int ret;
+ NBDExport *exp = client->exp;
+
+ assert(request->type == NBD_CMD_READ);
+
+ /* XXX: NBD Protocol only documents use of FUA with WRITE */
+ if (request->flags & NBD_CMD_FLAG_FUA) {
+ ret = blk_co_flush(exp->common.blk);
+ if (ret < 0) {
+ return nbd_send_generic_reply(client, request->handle, ret,
+ "flush failed", errp);
+ }
+ }
+
+ if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) &&
+ request->len)
+ {
+ return nbd_co_send_sparse_read(client, request->handle, request->from,
+ data, request->len, errp);
+ }
+
+ ret = blk_pread(exp->common.blk, request->from, data, request->len);
+ if (ret < 0) {
+ return nbd_send_generic_reply(client, request->handle, ret,
+ "reading from file failed", errp);
+ }
+
+ if (client->structured_reply) {
+ if (request->len) {
+ return nbd_co_send_structured_read(client, request->handle,
+ request->from, data,
+ request->len, true, errp);
+ } else {
+ return nbd_co_send_structured_done(client, request->handle, errp);
+ }
+ } else {
+ return nbd_co_send_simple_reply(client, request->handle, 0,
+ data, request->len, errp);
+ }
+}
+
+/*
+ * nbd_do_cmd_cache
+ *
+ * Handle NBD_CMD_CACHE request.
+ * Return -errno if sending fails. Other errors are reported directly to the
+ * client as an error reply.
+ */
+static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request,
+ Error **errp)
+{
+ int ret;
+ NBDExport *exp = client->exp;
+
+ assert(request->type == NBD_CMD_CACHE);
+
+ ret = blk_co_preadv(exp->common.blk, request->from, request->len,
+ NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH);
+
+ return nbd_send_generic_reply(client, request->handle, ret,
+ "caching data failed", errp);
+}
+
+/* Handle NBD request.
+ * Return -errno if sending fails. Other errors are reported directly to the
+ * client as an error reply. */
+static coroutine_fn int nbd_handle_request(NBDClient *client,
+ NBDRequest *request,
+ uint8_t *data, Error **errp)
+{
+ int ret;
+ int flags;
+ NBDExport *exp = client->exp;
+ char *msg;
+ size_t i;
+
+ switch (request->type) {
+ case NBD_CMD_CACHE:
+ return nbd_do_cmd_cache(client, request, errp);
+
+ case NBD_CMD_READ:
+ return nbd_do_cmd_read(client, request, data, errp);
+
+ case NBD_CMD_WRITE:
+ flags = 0;
+ if (request->flags & NBD_CMD_FLAG_FUA) {
+ flags |= BDRV_REQ_FUA;
+ }
+ ret = blk_pwrite(exp->common.blk, request->from, data, request->len,
+ flags);
+ return nbd_send_generic_reply(client, request->handle, ret,
+ "writing to file failed", errp);
+
+ case NBD_CMD_WRITE_ZEROES:
+ 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;
+ }
+ if (request->flags & NBD_CMD_FLAG_FAST_ZERO) {
+ flags |= BDRV_REQ_NO_FALLBACK;
+ }
+ ret = blk_pwrite_zeroes(exp->common.blk, request->from, request->len,
+ flags);
+ return nbd_send_generic_reply(client, request->handle, ret,
+ "writing to file failed", errp);
+
+ case NBD_CMD_DISC:
+ /* unreachable, thanks to special case in nbd_co_receive_request() */
+ abort();
+
+ case NBD_CMD_FLUSH:
+ ret = blk_co_flush(exp->common.blk);
+ return nbd_send_generic_reply(client, request->handle, ret,
+ "flush failed", errp);
+
+ case NBD_CMD_TRIM:
+ ret = blk_co_pdiscard(exp->common.blk, request->from, request->len);
+ if (ret >= 0 && request->flags & NBD_CMD_FLAG_FUA) {
+ ret = blk_co_flush(exp->common.blk);
+ }
+ return nbd_send_generic_reply(client, request->handle, ret,
+ "discard failed", errp);
+
+ case NBD_CMD_BLOCK_STATUS:
+ if (!request->len) {
+ return nbd_send_generic_reply(client, request->handle, -EINVAL,
+ "need non-zero length", errp);
+ }
+ if (client->export_meta.count) {
+ bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE;
+ int contexts_remaining = client->export_meta.count;
+
+ if (client->export_meta.base_allocation) {
+ ret = nbd_co_send_block_status(client, request->handle,
+ blk_bs(exp->common.blk),
+ request->from,
+ request->len, dont_fragment,
+ !--contexts_remaining,
+ NBD_META_ID_BASE_ALLOCATION,
+ errp);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ if (client->export_meta.allocation_depth) {
+ ret = nbd_co_send_block_status(client, request->handle,
+ blk_bs(exp->common.blk),
+ request->from, request->len,
+ dont_fragment,
+ !--contexts_remaining,
+ NBD_META_ID_ALLOCATION_DEPTH,
+ errp);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ for (i = 0; i < client->exp->nr_export_bitmaps; i++) {
+ if (!client->export_meta.bitmaps[i]) {
+ continue;
+ }
+ ret = nbd_co_send_bitmap(client, request->handle,
+ client->exp->export_bitmaps[i],
+ request->from, request->len,
+ dont_fragment, !--contexts_remaining,
+ NBD_META_ID_DIRTY_BITMAP + i, errp);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ assert(!contexts_remaining);
+
+ return 0;
+ } else {
+ return nbd_send_generic_reply(client, request->handle, -EINVAL,
+ "CMD_BLOCK_STATUS not negotiated",
+ errp);
+ }
+
+ default:
+ msg = g_strdup_printf("invalid request type (%" PRIu32 ") received",
+ request->type);
+ ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg,
+ errp);
+ g_free(msg);
+ return ret;
+ }
+}
+
+/* Owns a reference to the NBDClient passed as opaque. */
+static coroutine_fn void nbd_trip(void *opaque)
+{
+ NBDClient *client = opaque;
+ NBDRequestData *req;
+ NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */
+ int ret;
+ Error *local_err = NULL;
+
+ trace_nbd_trip();
+ if (client->closing) {
+ nbd_client_put(client);
+ return;
+ }
+
+ if (client->quiescing) {
+ /*
+ * We're switching between AIO contexts. Don't attempt to receive a new
+ * request and kick the main context which may be waiting for us.
+ */
+ nbd_client_put(client);
+ client->recv_coroutine = NULL;
+ aio_wait_kick();
+ return;
+ }
+
+ req = nbd_request_get(client);
+ ret = nbd_co_receive_request(req, &request, &local_err);
+ client->recv_coroutine = NULL;
+
+ if (client->closing) {
+ /*
+ * The client may be closed when we are blocked in
+ * nbd_co_receive_request()
+ */
+ goto done;
+ }
+
+ if (ret == -EAGAIN) {
+ assert(client->quiescing);
+ goto done;
+ }
+
+ nbd_client_receive_next_request(client);
+ if (ret == -EIO) {
+ goto disconnect;
+ }
+
+ if (ret < 0) {
+ /* It wans't -EIO, so, according to nbd_co_receive_request()
+ * semantics, we should return the error to the client. */
+ Error *export_err = local_err;
+
+ local_err = NULL;
+ ret = nbd_send_generic_reply(client, request.handle, -EINVAL,
+ error_get_pretty(export_err), &local_err);
+ error_free(export_err);
+ } else {
+ ret = nbd_handle_request(client, &request, req->data, &local_err);
+ }
+ if (ret < 0) {
+ error_prepend(&local_err, "Failed to send reply: ");
+ goto disconnect;
+ }
+
+ /* We must disconnect after NBD_CMD_WRITE if we did not
+ * read the payload.
+ */
+ if (!req->complete) {
+ error_setg(&local_err, "Request handling failed in intermediate state");
+ goto disconnect;
+ }
+
+done:
+ nbd_request_put(req);
+ nbd_client_put(client);
+ return;
+
+disconnect:
+ if (local_err) {
+ error_reportf_err(local_err, "Disconnect client, due to: ");
+ }
+ nbd_request_put(req);
+ client_close(client, true);
+ nbd_client_put(client);
+}
+
+static void nbd_client_receive_next_request(NBDClient *client)
+{
+ if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS &&
+ !client->quiescing) {
+ nbd_client_get(client);
+ client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
+ aio_co_schedule(client->exp->common.ctx, client->recv_coroutine);
+ }
+}
+
+static coroutine_fn void nbd_co_client_start(void *opaque)
+{
+ NBDClient *client = opaque;
+ Error *local_err = NULL;
+
+ qemu_co_mutex_init(&client->send_lock);
+
+ if (nbd_negotiate(client, &local_err)) {
+ if (local_err) {
+ error_report_err(local_err);
+ }
+ client_close(client, false);
+ return;
+ }
+
+ nbd_client_receive_next_request(client);
+}
+
+/*
+ * Create a new client listener using the given channel @sioc.
+ * Begin servicing it in a coroutine. When the connection closes, call
+ * @close_fn with an indication of whether the client completed negotiation.
+ */
+void nbd_client_new(QIOChannelSocket *sioc,
+ QCryptoTLSCreds *tlscreds,
+ const char *tlsauthz,
+ void (*close_fn)(NBDClient *, bool))
+{
+ NBDClient *client;
+ Coroutine *co;
+
+ client = g_new0(NBDClient, 1);
+ client->refcount = 1;
+ client->tlscreds = tlscreds;
+ if (tlscreds) {
+ object_ref(OBJECT(client->tlscreds));
+ }
+ client->tlsauthz = g_strdup(tlsauthz);
+ client->sioc = sioc;
+ object_ref(OBJECT(client->sioc));
+ client->ioc = QIO_CHANNEL(sioc);
+ object_ref(OBJECT(client->ioc));
+ client->close_fn = close_fn;
+
+ co = qemu_coroutine_create(nbd_co_client_start, client);
+ qemu_coroutine_enter(co);
+}