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qemu/nbd/server.c
Eric Blake b9b72cb3ce nbd/server: CVE-2024-7409: Drop non-negotiating clients 
A client that opens a socket but does not negotiate is merely hogging
qemu's resources (an open fd and a small amount of memory); and a
malicious client that can access the port where NBD is listening can
attempt a denial of service attack by intentionally opening and
abandoning lots of unfinished connections.  The previous patch put a
default bound on the number of such ongoing connections, but once that
limit is hit, no more clients can connect (including legitimate ones).
The solution is to insist that clients complete handshake within a
reasonable time limit, defaulting to 10 seconds.  A client that has
not successfully completed NBD_OPT_GO by then (including the case of
where the client didn't know TLS credentials to even reach the point
of NBD_OPT_GO) is wasting our time and does not deserve to stay
connected.  Later patches will allow fine-tuning the limit away from
the default value (including disabling it for doing integration
testing of the handshake process itself).

Note that this patch in isolation actually makes it more likely to see
qemu SEGV after nbd-server-stop, as any client socket still connected
when the server shuts down will now be closed after 10 seconds rather
than at the client's whims.  That will be addressed in the next patch.

For a demo of this patch in action:
$ qemu-nbd -f raw -r -t -e 10 file &
$ nbdsh --opt-mode -c '
H = list()
for i in range(20):
  print(i)
  H.insert(i, nbd.NBD())
  H[i].set_opt_mode(True)
  H[i].connect_uri("nbd://localhost")
'
$ kill $!

where later connections get to start progressing once earlier ones are
forcefully dropped for taking too long, rather than hanging.

Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-ID: <20240807174943.771624-13-eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
[eblake: rebase to changes earlier in series, reduce scope of timer]
Signed-off-by: Eric Blake <eblake@redhat.com>
2024-08-08 16:25:33 -05:00

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/*
* Copyright Red Hat
* 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/block_int.h"
#include "block/export.h"
#include "block/dirty-bitmap.h"
#include "qapi/error.h"
#include "qemu/queue.h"
#include "trace.h"
#include "nbd-internal.h"
#include "qemu/units.h"
#include "qemu/memalign.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 {
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);
/*
* NBDMetaContexts represents a list of meta contexts in use,
* as selected by NBD_OPT_SET_META_CONTEXT. Also used for
* NBD_OPT_LIST_META_CONTEXT.
*/
struct NBDMetaContexts {
const NBDExport *exp; /* associated export */
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
*/
};
struct NBDClient {
int refcount; /* atomic */
void (*close_fn)(NBDClient *client, bool negotiated);
void *owner;
QemuMutex lock;
NBDExport *exp;
QCryptoTLSCreds *tlscreds;
char *tlsauthz;
uint32_t handshake_max_secs;
QIOChannelSocket *sioc; /* The underlying data channel */
QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
Coroutine *recv_coroutine; /* protected by lock */
CoMutex send_lock;
Coroutine *send_coroutine;
bool read_yielding; /* protected by lock */
bool quiescing; /* protected by lock */
QTAILQ_ENTRY(NBDClient) next;
int nb_requests; /* protected by lock */
bool closing; /* protected by lock */
uint32_t check_align; /* If non-zero, check for aligned client requests */
NBDMode mode;
NBDMetaContexts contexts; /* Negotiated meta contexts */
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 coroutine_fn 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 coroutine_fn 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 coroutine_fn int G_GNUC_PRINTF(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 coroutine_fn int G_GNUC_PRINTF(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 coroutine_fn int G_GNUC_PRINTF(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 coroutine_fn int G_GNUC_PRINTF(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 coroutine_fn int G_GNUC_PRINTF(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 coroutine_fn 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 coroutine_fn 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 coroutine_fn 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 coroutine_fn 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 coroutine_fn 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 coroutine_fn void
nbd_check_meta_export(NBDClient *client, NBDExport *exp)
{
if (exp != client->contexts.exp) {
client->contexts.count = 0;
}
}
/* Send a reply to NBD_OPT_EXPORT_NAME.
* Return -errno on error, 0 on success. */
static coroutine_fn 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->mode >= NBD_MODE_EXTENDED) {
error_setg(errp, "Extended headers already negotiated");
return -EINVAL;
}
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;
}
nbd_check_meta_export(client, client->exp);
myflags = client->exp->nbdflags;
if (client->mode >= NBD_MODE_STRUCTURED) {
myflags |= NBD_FLAG_SEND_DF;
}
if (client->mode >= NBD_MODE_EXTENDED && client->contexts.count) {
myflags |= NBD_FLAG_BLOCK_STAT_PAYLOAD;
}
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);
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 coroutine_fn 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 coroutine_fn 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 coroutine_fn 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);
}
if (client->opt == NBD_OPT_GO) {
nbd_check_meta_export(client, exp);
}
/* 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->mode >= NBD_MODE_STRUCTURED) {
myflags |= NBD_FLAG_SEND_DF;
}
if (client->mode >= NBD_MODE_EXTENDED &&
(client->contexts.count || client->opt == NBD_OPT_INFO)) {
myflags |= NBD_FLAG_BLOCK_STAT_PAYLOAD;
}
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);
rc = 1;
}
return rc;
}
/* Callback to learn when QIO TLS upgrade is complete */
struct NBDTLSServerHandshakeData {
bool complete;
Error *error;
Coroutine *co;
};
static void
nbd_server_tls_handshake(QIOTask *task, void *opaque)
{
struct NBDTLSServerHandshakeData *data = opaque;
qio_task_propagate_error(task, &data->error);
data->complete = true;
if (!qemu_coroutine_entered(data->co)) {
aio_co_wake(data->co);
}
}
/* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
* new channel for all further (now-encrypted) communication. */
static coroutine_fn QIOChannel *
nbd_negotiate_handle_starttls(NBDClient *client, Error **errp)
{
QIOChannel *ioc;
QIOChannelTLS *tioc;
struct NBDTLSServerHandshakeData 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.co = qemu_coroutine_self();
qio_channel_tls_handshake(tioc,
nbd_server_tls_handshake,
&data,
NULL,
NULL);
if (!data.complete) {
qemu_coroutine_yield();
assert(data.complete);
}
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 coroutine_fn 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 coroutine_fn 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 coroutine_fn 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 coroutine_fn bool
nbd_meta_base_query(NBDClient *client, NBDMetaContexts *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 coroutine_fn bool
nbd_meta_qemu_query(NBDClient *client, NBDMetaContexts *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 coroutine_fn int
nbd_negotiate_meta_query(NBDClient *client,
NBDMetaContexts *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 coroutine_fn int
nbd_negotiate_meta_queries(NBDClient *client, 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;
NBDMetaContexts local_meta = {0};
NBDMetaContexts *meta;
uint32_t nb_queries;
size_t i;
size_t count = 0;
if (client->opt == NBD_OPT_SET_META_CONTEXT &&
client->mode < NBD_MODE_STRUCTURED) {
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;
} else {
meta = &client->contexts;
}
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 coroutine_fn 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;
}
client->mode = NBD_MODE_EXPORT_NAME;
trace_nbd_negotiate_options_flags(flags);
if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
fixedNewstyle = true;
flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
client->mode = NBD_MODE_SIMPLE;
}
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 = 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->mode >= NBD_MODE_EXTENDED) {
ret = nbd_negotiate_send_rep_err(
client, NBD_REP_ERR_EXT_HEADER_REQD, errp,
"extended headers already negotiated");
} else if (client->mode >= NBD_MODE_STRUCTURED) {
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->mode = NBD_MODE_STRUCTURED;
}
break;
case NBD_OPT_LIST_META_CONTEXT:
case NBD_OPT_SET_META_CONTEXT:
ret = nbd_negotiate_meta_queries(client, errp);
break;
case NBD_OPT_EXTENDED_HEADERS:
if (length) {
ret = nbd_reject_length(client, false, errp);
} else if (client->mode >= NBD_MODE_EXTENDED) {
ret = nbd_negotiate_send_rep_err(
client, NBD_REP_ERR_INVALID, errp,
"extended headers already negotiated");
} else {
ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
client->mode = NBD_MODE_EXTENDED;
}
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);
qio_channel_set_follow_coroutine_ctx(client->ioc, true);
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;
}
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) {
WITH_QEMU_LOCK_GUARD(&client->lock) {
client->read_yielding = true;
/* Prompt main loop thread to re-run nbd_drained_poll() */
aio_wait_kick();
}
qio_channel_yield(client->ioc, G_IO_IN);
WITH_QEMU_LOCK_GUARD(&client->lock) {
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 coroutine_fn nbd_receive_request(NBDClient *client, NBDRequest *request,
Error **errp)
{
uint8_t buf[NBD_EXTENDED_REQUEST_SIZE];
uint32_t magic, expect;
int ret;
size_t size = client->mode >= NBD_MODE_EXTENDED ?
NBD_EXTENDED_REQUEST_SIZE : NBD_REQUEST_SIZE;
ret = nbd_read_eof(client, buf, size, errp);
if (ret < 0) {
return ret;
}
if (ret == 0) {
return -EIO;
}
/*
* Compact request
* [ 0 .. 3] magic (NBD_REQUEST_MAGIC)
* [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...)
* [ 6 .. 7] type (NBD_CMD_READ, ...)
* [ 8 .. 15] cookie
* [16 .. 23] from
* [24 .. 27] len
* Extended request
* [ 0 .. 3] magic (NBD_EXTENDED_REQUEST_MAGIC)
* [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, NBD_CMD_FLAG_PAYLOAD_LEN, ...)
* [ 6 .. 7] type (NBD_CMD_READ, ...)
* [ 8 .. 15] cookie
* [16 .. 23] from
* [24 .. 31] len
*/
magic = ldl_be_p(buf);
request->flags = lduw_be_p(buf + 4);
request->type = lduw_be_p(buf + 6);
request->cookie = ldq_be_p(buf + 8);
request->from = ldq_be_p(buf + 16);
if (client->mode >= NBD_MODE_EXTENDED) {
request->len = ldq_be_p(buf + 24);
expect = NBD_EXTENDED_REQUEST_MAGIC;
} else {
request->len = (uint32_t)ldl_be_p(buf + 24); /* widen 32 to 64 bits */
expect = NBD_REQUEST_MAGIC;
}
trace_nbd_receive_request(magic, request->flags, request->type,
request->from, request->len);
if (magic != expect) {
error_setg(errp, "invalid magic (got 0x%" PRIx32 ", expected 0x%"
PRIx32 ")", magic, expect);
return -EINVAL;
}
return 0;
}
#define MAX_NBD_REQUESTS 16
/* Runs in export AioContext and main loop thread */
void nbd_client_get(NBDClient *client)
{
qatomic_inc(&client->refcount);
}
void nbd_client_put(NBDClient *client)
{
assert(qemu_in_main_thread());
if (qatomic_fetch_dec(&client->refcount) == 1) {
/* The last reference should be dropped by client->close,
* which is called by client_close.
*/
assert(client->closing);
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->contexts.bitmaps);
qemu_mutex_destroy(&client->lock);
g_free(client);
}
}
/*
* Tries to release the reference to @client, but only if other references
* remain. This is an optimization for the common case where we want to avoid
* the expense of scheduling nbd_client_put() in the main loop thread.
*
* Returns true upon success or false if the reference was not released because
* it is the last reference.
*/
static bool nbd_client_put_nonzero(NBDClient *client)
{
int old = qatomic_read(&client->refcount);
int expected;
do {
if (old == 1) {
return false;
}
expected = old;
old = qatomic_cmpxchg(&client->refcount, expected, expected - 1);
} while (old != expected);
return true;
}
static void client_close(NBDClient *client, bool negotiated)
{
assert(qemu_in_main_thread());
WITH_QEMU_LOCK_GUARD(&client->lock) {
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);
}
}
/* Runs in export AioContext with client->lock held */
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);
req->client = client;
return req;
}
/* Runs in export AioContext with client->lock held */
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);
}
static void blk_aio_attached(AioContext *ctx, void *opaque)
{
NBDExport *exp = opaque;
NBDClient *client;
assert(qemu_in_main_thread());
trace_nbd_blk_aio_attached(exp->name, ctx);
exp->common.ctx = ctx;
QTAILQ_FOREACH(client, &exp->clients, next) {
WITH_QEMU_LOCK_GUARD(&client->lock) {
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;
assert(qemu_in_main_thread());
trace_nbd_blk_aio_detach(exp->name, exp->common.ctx);
exp->common.ctx = NULL;
}
static void nbd_drained_begin(void *opaque)
{
NBDExport *exp = opaque;
NBDClient *client;
assert(qemu_in_main_thread());
QTAILQ_FOREACH(client, &exp->clients, next) {
WITH_QEMU_LOCK_GUARD(&client->lock) {
client->quiescing = true;
}
}
}
static void nbd_drained_end(void *opaque)
{
NBDExport *exp = opaque;
NBDClient *client;
assert(qemu_in_main_thread());
QTAILQ_FOREACH(client, &exp->clients, next) {
WITH_QEMU_LOCK_GUARD(&client->lock) {
client->quiescing = false;
nbd_client_receive_next_request(client);
}
}
}
/* Runs in export AioContext */
static void nbd_wake_read_bh(void *opaque)
{
NBDClient *client = opaque;
qio_channel_wake_read(client->ioc);
}
static bool nbd_drained_poll(void *opaque)
{
NBDExport *exp = opaque;
NBDClient *client;
assert(qemu_in_main_thread());
QTAILQ_FOREACH(client, &exp->clients, next) {
WITH_QEMU_LOCK_GUARD(&client->lock) {
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.
*
* Schedule a BH in the export AioContext to avoid missing the
* wake up due to the race between qio_channel_wake_read() and
* qio_channel_yield().
*/
if (client->recv_coroutine != NULL && client->read_yielding) {
aio_bh_schedule_oneshot(nbd_export_aio_context(client->exp),
nbd_wake_read_bh, client);
}
return true;
}
}
}
return false;
}
static void nbd_eject_notifier(Notifier *n, void *data)
{
NBDExport *exp = container_of(n, NBDExport, eject_notifier);
assert(qemu_in_main_thread());
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;
const char *name = arg->name ?: exp_args->node_name;
BlockBackend *blk = blk_exp->blk;
int64_t size;
uint64_t perm, shared_perm;
bool readonly = !exp_args->writable;
BlockDirtyBitmapOrStrList *bitmaps;
size_t i;
int ret;
GLOBAL_STATE_CODE();
assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD);
if (!nbd_server_is_running()) {
error_setg(errp, "NBD server not running");
return -EINVAL;
}
if (strlen(name) > NBD_MAX_STRING_SIZE) {
error_setg(errp, "export name '%s' too long", 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(name)) {
error_setg(errp, "NBD server already has export named '%s'", 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(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 (nbd_server_max_connections() != 1) {
exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN;
}
if (readonly) {
exp->nbdflags |= NBD_FLAG_READ_ONLY;
} 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);
bdrv_graph_rdlock_main_loop();
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;
BlockDriverState *bs = blk_bs(blk);
BdrvDirtyBitmap *bm = NULL;
switch (bitmaps->value->type) {
case QTYPE_QSTRING:
bitmap = bitmaps->value->u.local;
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",
bitmaps->value->u.local);
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;
}
break;
case QTYPE_QDICT:
bitmap = bitmaps->value->u.external.name;
bm = block_dirty_bitmap_lookup(bitmaps->value->u.external.node,
bitmap, NULL, errp);
if (!bm) {
ret = -ENOENT;
goto fail;
}
break;
default:
abort();
}
assert(bm);
if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) {
ret = -EINVAL;
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);
bdrv_graph_rdunlock_main_loop();
return 0;
fail:
bdrv_graph_rdunlock_main_loop();
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 BlockExportRemoveMode 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->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 cookie)
{
stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);
stl_be_p(&reply->error, error);
stq_be_p(&reply->cookie, cookie);
}
static int coroutine_fn nbd_co_send_simple_reply(NBDClient *client,
NBDRequest *request,
uint32_t error,
void *data,
uint64_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}
};
assert(!len || !nbd_err);
assert(len <= NBD_MAX_BUFFER_SIZE);
assert(client->mode < NBD_MODE_STRUCTURED ||
(client->mode == NBD_MODE_STRUCTURED &&
request->type != NBD_CMD_READ));
trace_nbd_co_send_simple_reply(request->cookie, nbd_err,
nbd_err_lookup(nbd_err), len);
set_be_simple_reply(&reply, nbd_err, request->cookie);
return nbd_co_send_iov(client, iov, 2, errp);
}
/*
* Prepare the header of a reply chunk for network transmission.
*
* On input, @iov is partially initialized: iov[0].iov_base must point
* to an uninitialized NBDReply, while the remaining @niov elements
* (if any) must be ready for transmission. This function then
* populates iov[0] for transmission.
*/
static inline void set_be_chunk(NBDClient *client, struct iovec *iov,
size_t niov, uint16_t flags, uint16_t type,
NBDRequest *request)
{
size_t i, length = 0;
for (i = 1; i < niov; i++) {
length += iov[i].iov_len;
}
assert(length <= NBD_MAX_BUFFER_SIZE + sizeof(NBDStructuredReadData));
if (client->mode >= NBD_MODE_EXTENDED) {
NBDExtendedReplyChunk *chunk = iov->iov_base;
iov[0].iov_len = sizeof(*chunk);
stl_be_p(&chunk->magic, NBD_EXTENDED_REPLY_MAGIC);
stw_be_p(&chunk->flags, flags);
stw_be_p(&chunk->type, type);
stq_be_p(&chunk->cookie, request->cookie);
stq_be_p(&chunk->offset, request->from);
stq_be_p(&chunk->length, length);
} else {
NBDStructuredReplyChunk *chunk = iov->iov_base;
iov[0].iov_len = sizeof(*chunk);
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->cookie, request->cookie);
stl_be_p(&chunk->length, length);
}
}
static int coroutine_fn nbd_co_send_chunk_done(NBDClient *client,
NBDRequest *request,
Error **errp)
{
NBDReply hdr;
struct iovec iov[] = {
{.iov_base = &hdr},
};
trace_nbd_co_send_chunk_done(request->cookie);
set_be_chunk(client, iov, 1, NBD_REPLY_FLAG_DONE,
NBD_REPLY_TYPE_NONE, request);
return nbd_co_send_iov(client, iov, 1, errp);
}
static int coroutine_fn nbd_co_send_chunk_read(NBDClient *client,
NBDRequest *request,
uint64_t offset,
void *data,
uint64_t size,
bool final,
Error **errp)
{
NBDReply hdr;
NBDStructuredReadData chunk;
struct iovec iov[] = {
{.iov_base = &hdr},
{.iov_base = &chunk, .iov_len = sizeof(chunk)},
{.iov_base = data, .iov_len = size}
};
assert(size && size <= NBD_MAX_BUFFER_SIZE);
trace_nbd_co_send_chunk_read(request->cookie, offset, data, size);
set_be_chunk(client, iov, 3, final ? NBD_REPLY_FLAG_DONE : 0,
NBD_REPLY_TYPE_OFFSET_DATA, request);
stq_be_p(&chunk.offset, offset);
return nbd_co_send_iov(client, iov, 3, errp);
}
static int coroutine_fn nbd_co_send_chunk_error(NBDClient *client,
NBDRequest *request,
uint32_t error,
const char *msg,
Error **errp)
{
NBDReply hdr;
NBDStructuredError chunk;
int nbd_err = system_errno_to_nbd_errno(error);
struct iovec iov[] = {
{.iov_base = &hdr},
{.iov_base = &chunk, .iov_len = sizeof(chunk)},
{.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0},
};
assert(nbd_err);
trace_nbd_co_send_chunk_error(request->cookie, nbd_err,
nbd_err_lookup(nbd_err), msg ? msg : "");
set_be_chunk(client, iov, 3, NBD_REPLY_FLAG_DONE,
NBD_REPLY_TYPE_ERROR, request);
stl_be_p(&chunk.error, nbd_err);
stw_be_p(&chunk.message_length, iov[2].iov_len);
return nbd_co_send_iov(client, iov, 3, errp);
}
/* Do a sparse read and send the structured reply to the client.
* Returns -errno if sending fails. blk_co_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,
NBDRequest *request,
uint64_t offset,
uint8_t *data,
uint64_t size,
Error **errp)
{
int ret = 0;
NBDExport *exp = client->exp;
size_t progress = 0;
assert(size <= NBD_MAX_BUFFER_SIZE);
while (progress < size) {
int64_t pnum;
int status = blk_co_block_status_above(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_chunk_error(client, request, -status, msg, errp);
g_free(msg);
return ret;
}
assert(pnum && pnum <= size - progress);
final = progress + pnum == size;
if (status & BDRV_BLOCK_ZERO) {
NBDReply hdr;
NBDStructuredReadHole chunk;
struct iovec iov[] = {
{.iov_base = &hdr},
{.iov_base = &chunk, .iov_len = sizeof(chunk)},
};
trace_nbd_co_send_chunk_read_hole(request->cookie,
offset + progress, pnum);
set_be_chunk(client, iov, 2,
final ? NBD_REPLY_FLAG_DONE : 0,
NBD_REPLY_TYPE_OFFSET_HOLE, request);
stq_be_p(&chunk.offset, offset + progress);
stl_be_p(&chunk.length, pnum);
ret = nbd_co_send_iov(client, iov, 2, errp);
} else {
ret = blk_co_pread(exp->common.blk, offset + progress, pnum,
data + progress, 0);
if (ret < 0) {
error_setg_errno(errp, -ret, "reading from file failed");
break;
}
ret = nbd_co_send_chunk_read(client, request, offset + progress,
data + progress, pnum, final, errp);
}
if (ret < 0) {
break;
}
progress += pnum;
}
return ret;
}
typedef struct NBDExtentArray {
NBDExtent64 *extents;
unsigned int nb_alloc;
unsigned int count;
uint64_t total_length;
bool extended;
bool can_add;
bool converted_to_be;
} NBDExtentArray;
static NBDExtentArray *nbd_extent_array_new(unsigned int nb_alloc,
NBDMode mode)
{
NBDExtentArray *ea = g_new0(NBDExtentArray, 1);
assert(mode >= NBD_MODE_STRUCTURED);
ea->nb_alloc = nb_alloc;
ea->extents = g_new(NBDExtent64, nb_alloc);
ea->extended = mode >= NBD_MODE_EXTENDED;
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);
assert(ea->extended);
ea->can_add = false;
ea->converted_to_be = true;
for (i = 0; i < ea->count; i++) {
ea->extents[i].length = cpu_to_be64(ea->extents[i].length);
ea->extents[i].flags = cpu_to_be64(ea->extents[i].flags);
}
}
/* Further modifications of the array after conversion are abandoned */
static NBDExtent32 *nbd_extent_array_convert_to_narrow(NBDExtentArray *ea)
{
int i;
NBDExtent32 *extents = g_new(NBDExtent32, ea->count);
assert(!ea->converted_to_be);
assert(!ea->extended);
ea->can_add = false;
ea->converted_to_be = true;
for (i = 0; i < ea->count; i++) {
assert((ea->extents[i].length | ea->extents[i].flags) <= UINT32_MAX);
extents[i].length = cpu_to_be32(ea->extents[i].length);
extents[i].flags = cpu_to_be32(ea->extents[i].flags);
}
return extents;
}
/*
* 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,
* and further calls to nbd_extent_array_add() will crash.
* (this avoids the situation where a caller ignores failure to add one extent,
* where adding another extent that would squash into the last array entry
* would result in an incorrect range reported to the client)
*/
static int nbd_extent_array_add(NBDExtentArray *ea,
uint64_t length, uint32_t flags)
{
assert(ea->can_add);
if (!length) {
return 0;
}
if (!ea->extended) {
assert(length <= UINT32_MAX);
}
/* Extend previous extent if flags are the same */
if (ea->count > 0 && flags == ea->extents[ea->count - 1].flags) {
uint64_t sum = length + ea->extents[ea->count - 1].length;
/*
* sum cannot overflow: the block layer bounds image size at
* 2^63, and ea->extents[].length comes from the block layer.
*/
assert(sum >= length);
if (sum <= UINT32_MAX || ea->extended) {
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] = (NBDExtent64) {.length = length, .flags = flags};
ea->count++;
return 0;
}
static int coroutine_fn blockstatus_to_extents(BlockBackend *blk,
uint64_t offset, uint64_t bytes,
NBDExtentArray *ea)
{
while (bytes) {
uint32_t flags;
int64_t num;
int ret = blk_co_block_status_above(blk, 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 coroutine_fn blockalloc_to_extents(BlockBackend *blk,
uint64_t offset, uint64_t bytes,
NBDExtentArray *ea)
{
while (bytes) {
int64_t num;
int ret = blk_co_is_allocated_above(blk, 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 coroutine_fn
nbd_co_send_extents(NBDClient *client, NBDRequest *request, NBDExtentArray *ea,
bool last, uint32_t context_id, Error **errp)
{
NBDReply hdr;
NBDStructuredMeta meta;
NBDExtendedMeta meta_ext;
g_autofree NBDExtent32 *extents = NULL;
uint16_t type;
struct iovec iov[] = { {.iov_base = &hdr}, {0}, {0} };
if (client->mode >= NBD_MODE_EXTENDED) {
type = NBD_REPLY_TYPE_BLOCK_STATUS_EXT;
iov[1].iov_base = &meta_ext;
iov[1].iov_len = sizeof(meta_ext);
stl_be_p(&meta_ext.context_id, context_id);
stl_be_p(&meta_ext.count, ea->count);
nbd_extent_array_convert_to_be(ea);
iov[2].iov_base = ea->extents;
iov[2].iov_len = ea->count * sizeof(ea->extents[0]);
} else {
type = NBD_REPLY_TYPE_BLOCK_STATUS;
iov[1].iov_base = &meta;
iov[1].iov_len = sizeof(meta);
stl_be_p(&meta.context_id, context_id);
extents = nbd_extent_array_convert_to_narrow(ea);
iov[2].iov_base = extents;
iov[2].iov_len = ea->count * sizeof(extents[0]);
}
trace_nbd_co_send_extents(request->cookie, ea->count, context_id,
ea->total_length, last);
set_be_chunk(client, iov, 3, last ? NBD_REPLY_FLAG_DONE : 0, type,
request);
return nbd_co_send_iov(client, iov, 3, errp);
}
/* Get block status from the exported device and send it to the client */
static int
coroutine_fn nbd_co_send_block_status(NBDClient *client, NBDRequest *request,
BlockBackend *blk, uint64_t offset,
uint64_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, client->mode);
if (context_id == NBD_META_ID_BASE_ALLOCATION) {
ret = blockstatus_to_extents(blk, offset, length, ea);
} else {
ret = blockalloc_to_extents(blk, offset, length, ea);
}
if (ret < 0) {
return nbd_co_send_chunk_error(client, request, -ret,
"can't get block status", errp);
}
return nbd_co_send_extents(client, request, 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;
int64_t bound = es->extended ? INT64_MAX : INT32_MAX;
bdrv_dirty_bitmap_lock(bitmap);
for (start = offset;
bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, bound,
&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 coroutine_fn nbd_co_send_bitmap(NBDClient *client,
NBDRequest *request,
BdrvDirtyBitmap *bitmap,
uint64_t offset,
uint64_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, client->mode);
bitmap_to_extents(bitmap, offset, length, ea);
return nbd_co_send_extents(client, request, ea, last, context_id, errp);
}
/*
* nbd_co_block_status_payload_read
* Called when a client wants a subset of negotiated contexts via a
* BLOCK_STATUS payload. Check the payload for valid length and
* contents. On success, return 0 with request updated to effective
* length. If request was invalid but all payload consumed, return 0
* with request->len and request->contexts->count set to 0 (which will
* trigger an appropriate NBD_EINVAL response later on). Return
* negative errno if the payload was not fully consumed.
*/
static int
nbd_co_block_status_payload_read(NBDClient *client, NBDRequest *request,
Error **errp)
{
uint64_t payload_len = request->len;
g_autofree char *buf = NULL;
size_t count, i, nr_bitmaps;
uint32_t id;
if (payload_len > NBD_MAX_BUFFER_SIZE) {
error_setg(errp, "len (%" PRIu64 ") is larger than max len (%u)",
request->len, NBD_MAX_BUFFER_SIZE);
return -EINVAL;
}
assert(client->contexts.exp == client->exp);
nr_bitmaps = client->exp->nr_export_bitmaps;
request->contexts = g_new0(NBDMetaContexts, 1);
request->contexts->exp = client->exp;
if (payload_len % sizeof(uint32_t) ||
payload_len < sizeof(NBDBlockStatusPayload) ||
payload_len > (sizeof(NBDBlockStatusPayload) +
sizeof(id) * client->contexts.count)) {
goto skip;
}
buf = g_malloc(payload_len);
if (nbd_read(client->ioc, buf, payload_len,
"CMD_BLOCK_STATUS data", errp) < 0) {
return -EIO;
}
trace_nbd_co_receive_request_payload_received(request->cookie,
payload_len);
request->contexts->bitmaps = g_new0(bool, nr_bitmaps);
count = (payload_len - sizeof(NBDBlockStatusPayload)) / sizeof(id);
payload_len = 0;
for (i = 0; i < count; i++) {
id = ldl_be_p(buf + sizeof(NBDBlockStatusPayload) + sizeof(id) * i);
if (id == NBD_META_ID_BASE_ALLOCATION) {
if (!client->contexts.base_allocation ||
request->contexts->base_allocation) {
goto skip;
}
request->contexts->base_allocation = true;
} else if (id == NBD_META_ID_ALLOCATION_DEPTH) {
if (!client->contexts.allocation_depth ||
request->contexts->allocation_depth) {
goto skip;
}
request->contexts->allocation_depth = true;
} else {
unsigned idx = id - NBD_META_ID_DIRTY_BITMAP;
if (idx >= nr_bitmaps || !client->contexts.bitmaps[idx] ||
request->contexts->bitmaps[idx]) {
goto skip;
}
request->contexts->bitmaps[idx] = true;
}
}
request->len = ldq_be_p(buf);
request->contexts->count = count;
return 0;
skip:
trace_nbd_co_receive_block_status_payload_compliance(request->from,
request->len);
request->len = request->contexts->count = 0;
return nbd_drop(client->ioc, payload_len, 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 coroutine_fn nbd_co_receive_request(NBDRequestData *req,
NBDRequest *request,
Error **errp)
{
NBDClient *client = req->client;
bool extended_with_payload;
bool check_length = false;
bool check_rofs = false;
bool allocate_buffer = false;
bool payload_okay = false;
uint64_t payload_len = 0;
int valid_flags = NBD_CMD_FLAG_FUA;
int ret;
g_assert(qemu_in_coroutine());
ret = nbd_receive_request(client, request, errp);
if (ret < 0) {
return ret;
}
trace_nbd_co_receive_request_decode_type(request->cookie, request->type,
nbd_cmd_lookup(request->type));
extended_with_payload = client->mode >= NBD_MODE_EXTENDED &&
request->flags & NBD_CMD_FLAG_PAYLOAD_LEN;
if (extended_with_payload) {
payload_len = request->len;
check_length = true;
}
switch (request->type) {
case NBD_CMD_DISC:
/* Special case: we're going to disconnect without a reply,
* whether or not flags, from, or len are bogus */
req->complete = true;
return -EIO;
case NBD_CMD_READ:
if (client->mode >= NBD_MODE_STRUCTURED) {
valid_flags |= NBD_CMD_FLAG_DF;
}
check_length = true;
allocate_buffer = true;
break;
case NBD_CMD_WRITE:
if (client->mode >= NBD_MODE_EXTENDED) {
if (!extended_with_payload) {
/* The client is noncompliant. Trace it, but proceed. */
trace_nbd_co_receive_ext_payload_compliance(request->from,
request->len);
}
valid_flags |= NBD_CMD_FLAG_PAYLOAD_LEN;
}
payload_okay = true;
payload_len = request->len;
check_length = true;
allocate_buffer = true;
check_rofs = true;
break;
case NBD_CMD_FLUSH:
break;
case NBD_CMD_TRIM:
check_rofs = true;
break;
case NBD_CMD_CACHE:
check_length = true;
break;
case NBD_CMD_WRITE_ZEROES:
valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO;
check_rofs = true;
break;
case NBD_CMD_BLOCK_STATUS:
if (extended_with_payload) {
ret = nbd_co_block_status_payload_read(client, request, errp);
if (ret < 0) {
return ret;
}
/* payload now consumed */
check_length = false;
payload_len = 0;
valid_flags |= NBD_CMD_FLAG_PAYLOAD_LEN;
} else {
request->contexts = &client->contexts;
}
valid_flags |= NBD_CMD_FLAG_REQ_ONE;
break;
default:
/* Unrecognized, will fail later */
;
}
/* Payload and buffer handling. */
if (!payload_len) {
req->complete = true;
}
if (check_length && request->len > NBD_MAX_BUFFER_SIZE) {
/* READ, WRITE, CACHE */
error_setg(errp, "len (%" PRIu64 ") is larger than max len (%u)",
request->len, NBD_MAX_BUFFER_SIZE);
return -EINVAL;
}
if (payload_len && !payload_okay) {
/*
* For now, we don't support payloads on other commands; but
* we can keep the connection alive by ignoring the payload.
* We will fail the command later with NBD_EINVAL for the use
* of an unsupported flag (and not for access beyond bounds).
*/
assert(request->type != NBD_CMD_WRITE);
request->len = 0;
}
if (allocate_buffer) {
/* READ, WRITE */
req->data = blk_try_blockalign(client->exp->common.blk,
request->len);
if (req->data == NULL) {
error_setg(errp, "No memory");
return -ENOMEM;
}
}
if (payload_len) {
if (payload_okay) {
/* WRITE */
assert(req->data);
ret = nbd_read(client->ioc, req->data, payload_len,
"CMD_WRITE data", errp);
} else {
ret = nbd_drop(client->ioc, payload_len, errp);
}
if (ret < 0) {
return -EIO;
}
req->complete = true;
trace_nbd_co_receive_request_payload_received(request->cookie,
payload_len);
}
/* Sanity checks. */
if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && check_rofs) {
/* WRITE, TRIM, WRITE_ZEROES */
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: %" PRIu64
", 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);
}
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,
NBDRequest *request,
int ret,
const char *error_msg,
Error **errp)
{
if (client->mode >= NBD_MODE_STRUCTURED && ret < 0) {
return nbd_co_send_chunk_error(client, request, -ret, error_msg, errp);
} else if (client->mode >= NBD_MODE_EXTENDED) {
return nbd_co_send_chunk_done(client, request, errp);
} else {
return nbd_co_send_simple_reply(client, request, 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);
assert(request->len <= NBD_MAX_BUFFER_SIZE);
/* 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, ret,
"flush failed", errp);
}
}
if (client->mode >= NBD_MODE_STRUCTURED &&
!(request->flags & NBD_CMD_FLAG_DF) && request->len)
{
return nbd_co_send_sparse_read(client, request, request->from,
data, request->len, errp);
}
ret = blk_co_pread(exp->common.blk, request->from, request->len, data, 0);
if (ret < 0) {
return nbd_send_generic_reply(client, request, ret,
"reading from file failed", errp);
}
if (client->mode >= NBD_MODE_STRUCTURED) {
if (request->len) {
return nbd_co_send_chunk_read(client, request, request->from, data,
request->len, true, errp);
} else {
return nbd_co_send_chunk_done(client, request, errp);
}
} else {
return nbd_co_send_simple_reply(client, request, 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);
assert(request->len <= NBD_MAX_BUFFER_SIZE);
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, 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;
}
assert(request->len <= NBD_MAX_BUFFER_SIZE);
ret = blk_co_pwrite(exp->common.blk, request->from, request->len, data,
flags);
return nbd_send_generic_reply(client, request, 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_co_pwrite_zeroes(exp->common.blk, request->from, request->len,
flags);
return nbd_send_generic_reply(client, request, 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, 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, ret,
"discard failed", errp);
case NBD_CMD_BLOCK_STATUS:
assert(request->contexts);
assert(client->mode >= NBD_MODE_EXTENDED ||
request->len <= UINT32_MAX);
if (request->contexts->count) {
bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE;
int contexts_remaining = request->contexts->count;
if (!request->len) {
return nbd_send_generic_reply(client, request, -EINVAL,
"need non-zero length", errp);
}
if (request->contexts->base_allocation) {
ret = nbd_co_send_block_status(client, request,
exp->common.blk,
request->from,
request->len, dont_fragment,
!--contexts_remaining,
NBD_META_ID_BASE_ALLOCATION,
errp);
if (ret < 0) {
return ret;
}
}
if (request->contexts->allocation_depth) {
ret = nbd_co_send_block_status(client, request,
exp->common.blk,
request->from, request->len,
dont_fragment,
!--contexts_remaining,
NBD_META_ID_ALLOCATION_DEPTH,
errp);
if (ret < 0) {
return ret;
}
}
assert(request->contexts->exp == client->exp);
for (i = 0; i < client->exp->nr_export_bitmaps; i++) {
if (!request->contexts->bitmaps[i]) {
continue;
}
ret = nbd_co_send_bitmap(client, request,
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 if (client->contexts.count) {
return nbd_send_generic_reply(client, request, -EINVAL,
"CMD_BLOCK_STATUS payload not valid",
errp);
} else {
return nbd_send_generic_reply(client, request, -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, -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)
{
NBDRequestData *req = opaque;
NBDClient *client = req->client;
NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */
int ret;
Error *local_err = NULL;
/*
* Note that nbd_client_put() and client_close() must be called from the
* main loop thread. Use aio_co_reschedule_self() to switch AioContext
* before calling these functions.
*/
trace_nbd_trip();
qemu_mutex_lock(&client->lock);
if (client->closing) {
goto done;
}
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.
*/
client->recv_coroutine = NULL;
aio_wait_kick();
goto done;
}
/*
* nbd_co_receive_request() returns -EAGAIN when nbd_drained_begin() has
* set client->quiescing but by the time we get back nbd_drained_end() may
* have already cleared client->quiescing. In that case we try again
* because nothing else will spawn an nbd_trip() coroutine until we set
* client->recv_coroutine = NULL further down.
*/
do {
assert(client->recv_coroutine == qemu_coroutine_self());
qemu_mutex_unlock(&client->lock);
ret = nbd_co_receive_request(req, &request, &local_err);
qemu_mutex_lock(&client->lock);
} while (ret == -EAGAIN && !client->quiescing);
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) {
goto done;
}
nbd_client_receive_next_request(client);
if (ret == -EIO) {
goto disconnect;
}
qemu_mutex_unlock(&client->lock);
qio_channel_set_cork(client->ioc, true);
if (ret < 0) {
/* It wasn'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, -EINVAL,
error_get_pretty(export_err), &local_err);
error_free(export_err);
} else {
ret = nbd_handle_request(client, &request, req->data, &local_err);
}
if (request.contexts && request.contexts != &client->contexts) {
assert(request.type == NBD_CMD_BLOCK_STATUS);
g_free(request.contexts->bitmaps);
g_free(request.contexts);
}
qio_channel_set_cork(client->ioc, false);
qemu_mutex_lock(&client->lock);
if (ret < 0) {
error_prepend(&local_err, "Failed to send reply: ");
goto disconnect;
}
/*
* We must disconnect after NBD_CMD_WRITE or BLOCK_STATUS with
* payload 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);
qemu_mutex_unlock(&client->lock);
if (!nbd_client_put_nonzero(client)) {
aio_co_reschedule_self(qemu_get_aio_context());
nbd_client_put(client);
}
return;
disconnect:
if (local_err) {
error_reportf_err(local_err, "Disconnect client, due to: ");
}
nbd_request_put(req);
qemu_mutex_unlock(&client->lock);
aio_co_reschedule_self(qemu_get_aio_context());
client_close(client, true);
nbd_client_put(client);
}
/*
* Runs in export AioContext and main loop thread. Caller must hold
* client->lock.
*/
static void nbd_client_receive_next_request(NBDClient *client)
{
NBDRequestData *req;
if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS &&
!client->quiescing) {
nbd_client_get(client);
req = nbd_request_get(client);
client->recv_coroutine = qemu_coroutine_create(nbd_trip, req);
aio_co_schedule(client->exp->common.ctx, client->recv_coroutine);
}
}
static void nbd_handshake_timer_cb(void *opaque)
{
QIOChannel *ioc = opaque;
trace_nbd_handshake_timer_cb();
qio_channel_shutdown(ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
}
static coroutine_fn void nbd_co_client_start(void *opaque)
{
NBDClient *client = opaque;
Error *local_err = NULL;
QEMUTimer *handshake_timer = NULL;
qemu_co_mutex_init(&client->send_lock);
/*
* Create a timer to bound the time spent in negotiation. If the
* timer expires, it is likely nbd_negotiate will fail because the
* socket was shutdown.
*/
if (client->handshake_max_secs > 0) {
handshake_timer = aio_timer_new(qemu_get_aio_context(),
QEMU_CLOCK_REALTIME,
SCALE_NS,
nbd_handshake_timer_cb,
client->sioc);
timer_mod(handshake_timer,
qemu_clock_get_ns(QEMU_CLOCK_REALTIME) +
client->handshake_max_secs * NANOSECONDS_PER_SECOND);
}
if (nbd_negotiate(client, &local_err)) {
if (local_err) {
error_report_err(local_err);
}
timer_free(handshake_timer);
client_close(client, false);
return;
}
timer_free(handshake_timer);
WITH_QEMU_LOCK_GUARD(&client->lock) {
nbd_client_receive_next_request(client);
}
}
/*
* Create a new client listener using the given channel @sioc and @owner.
* Begin servicing it in a coroutine. When the connection closes, call
* @close_fn with an indication of whether the client completed negotiation
* within @handshake_max_secs seconds (0 for unbounded).
*/
void nbd_client_new(QIOChannelSocket *sioc,
uint32_t handshake_max_secs,
QCryptoTLSCreds *tlscreds,
const char *tlsauthz,
void (*close_fn)(NBDClient *, bool),
void *owner)
{
NBDClient *client;
Coroutine *co;
client = g_new0(NBDClient, 1);
qemu_mutex_init(&client->lock);
client->refcount = 1;
client->tlscreds = tlscreds;
if (tlscreds) {
object_ref(OBJECT(client->tlscreds));
}
client->tlsauthz = g_strdup(tlsauthz);
client->handshake_max_secs = handshake_max_secs;
client->sioc = sioc;
qio_channel_set_delay(QIO_CHANNEL(sioc), false);
object_ref(OBJECT(client->sioc));
client->ioc = QIO_CHANNEL(sioc);
object_ref(OBJECT(client->ioc));
client->close_fn = close_fn;
client->owner = owner;
co = qemu_coroutine_create(nbd_co_client_start, client);
qemu_coroutine_enter(co);
}
void *
nbd_client_owner(NBDClient *client)
{
return client->owner;
}
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