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Merge remote-tracking branch 'remotes/bonzini/nbd-next' into staging
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* remotes/bonzini/nbd-next:
  nbd: Handle NBD_OPT_LIST option.
  nbd: Handle fixed new-style clients.
  nbd: Shutdown socket before closing.
  nbd: Don't validate from and len in NBD_CMD_DISC.
  nbd: Don't export a block device with no medium.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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@pm215
pm215 committed Jun 30, 2014
2 parents ec9fe95 + 32d7d2e commit 8954000
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Showing 4 changed files with 186 additions and 49 deletions.
5 changes: 5 additions & 0 deletions blockdev-nbd.c
View file
Expand Up @@ -28,6 +28,7 @@ static void nbd_accept(void *opaque)

int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
if (fd >= 0 && !nbd_client_new(NULL, fd, nbd_client_put)) {
shutdown(fd, 2);
close(fd);
}
}
Expand Down Expand Up @@ -91,6 +92,10 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
error_set(errp, QERR_DEVICE_NOT_FOUND, device);
return;
}
if (!bdrv_is_inserted(bs)) {
error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
return;
}

if (!has_writable) {
writable = false;
Expand Down
12 changes: 12 additions & 0 deletions include/block/nbd.h
View file
Expand Up @@ -45,6 +45,18 @@ struct nbd_reply {
#define NBD_FLAG_ROTATIONAL (1 << 4) /* Use elevator algorithm - rotational media */
#define NBD_FLAG_SEND_TRIM (1 << 5) /* Send TRIM (discard) */

/* New-style global flags. */
#define NBD_FLAG_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */

/* New-style client flags. */
#define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */

/* Reply types. */
#define NBD_REP_ACK (1) /* Data sending finished. */
#define NBD_REP_SERVER (2) /* Export description. */
#define NBD_REP_ERR_UNSUP ((1 << 31) | 1) /* Unknown option. */
#define NBD_REP_ERR_INVALID ((1 << 31) | 3) /* Invalid length. */

#define NBD_CMD_MASK_COMMAND 0x0000ffff
#define NBD_CMD_FLAG_FUA (1 << 16)

Expand Down
217 changes: 168 additions & 49 deletions nbd.c
View file
Expand Up @@ -56,14 +56,19 @@
__FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
} while(0)

/* This is all part of the "official" NBD API */
/* This is all part of the "official" NBD API.
*
* The most up-to-date documentation is available at:
* https://github.com/yoe/nbd/blob/master/doc/proto.txt
*/

#define NBD_REQUEST_SIZE (4 + 4 + 8 + 8 + 4)
#define NBD_REPLY_SIZE (4 + 4 + 8)
#define NBD_REQUEST_MAGIC 0x25609513
#define NBD_REPLY_MAGIC 0x67446698
#define NBD_OPTS_MAGIC 0x49484156454F5054LL
#define NBD_CLIENT_MAGIC 0x0000420281861253LL
#define NBD_REP_MAGIC 0x3e889045565a9LL

#define NBD_SET_SOCK _IO(0xab, 0)
#define NBD_SET_BLKSIZE _IO(0xab, 1)
Expand All @@ -77,7 +82,9 @@
#define NBD_SET_TIMEOUT _IO(0xab, 9)
#define NBD_SET_FLAGS _IO(0xab, 10)

#define NBD_OPT_EXPORT_NAME (1 << 0)
#define NBD_OPT_EXPORT_NAME (1)
#define NBD_OPT_ABORT (2)
#define NBD_OPT_LIST (3)

/* Definitions for opaque data types */

Expand Down Expand Up @@ -215,59 +222,101 @@ static ssize_t write_sync(int fd, void *buffer, size_t size)
*/

static int nbd_receive_options(NBDClient *client)
static int nbd_send_rep(int csock, uint32_t type, uint32_t opt)
{
int csock = client->sock;
char name[256];
uint32_t tmp, length;
uint64_t magic;
int rc;
uint32_t len;

/* Client sends:
[ 0 .. 3] reserved (0)
[ 4 .. 11] NBD_OPTS_MAGIC
[12 .. 15] NBD_OPT_EXPORT_NAME
[16 .. 19] length
[20 .. xx] export name (length bytes)
*/

rc = -EINVAL;
if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
LOG("read failed");
goto fail;
magic = cpu_to_be64(NBD_REP_MAGIC);
if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
LOG("write failed (rep magic)");
return -EINVAL;
}
TRACE("Checking reserved");
if (tmp != 0) {
LOG("Bad reserved received");
goto fail;
opt = cpu_to_be32(opt);
if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
LOG("write failed (rep opt)");
return -EINVAL;
}

if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
LOG("read failed");
goto fail;
type = cpu_to_be32(type);
if (write_sync(csock, &type, sizeof(type)) != sizeof(type)) {
LOG("write failed (rep type)");
return -EINVAL;
}
TRACE("Checking reserved");
if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) {
LOG("Bad magic received");
goto fail;
len = cpu_to_be32(0);
if (write_sync(csock, &len, sizeof(len)) != sizeof(len)) {
LOG("write failed (rep data length)");
return -EINVAL;
}
return 0;
}

if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
LOG("read failed");
goto fail;
static int nbd_send_rep_list(int csock, NBDExport *exp)
{
uint64_t magic, name_len;
uint32_t opt, type, len;

name_len = strlen(exp->name);
magic = cpu_to_be64(NBD_REP_MAGIC);
if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
LOG("write failed (magic)");
return -EINVAL;
}
opt = cpu_to_be32(NBD_OPT_LIST);
if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
LOG("write failed (opt)");
return -EINVAL;
}
TRACE("Checking option");
if (tmp != be32_to_cpu(NBD_OPT_EXPORT_NAME)) {
LOG("Bad option received");
goto fail;
type = cpu_to_be32(NBD_REP_SERVER);
if (write_sync(csock, &type, sizeof(type)) != sizeof(type)) {
LOG("write failed (reply type)");
return -EINVAL;
}
len = cpu_to_be32(name_len + sizeof(len));
if (write_sync(csock, &len, sizeof(len)) != sizeof(len)) {
LOG("write failed (length)");
return -EINVAL;
}
len = cpu_to_be32(name_len);
if (write_sync(csock, &len, sizeof(len)) != sizeof(len)) {
LOG("write failed (length)");
return -EINVAL;
}
if (write_sync(csock, exp->name, name_len) != name_len) {
LOG("write failed (buffer)");
return -EINVAL;
}
return 0;
}

if (read_sync(csock, &length, sizeof(length)) != sizeof(length)) {
LOG("read failed");
goto fail;
static int nbd_handle_list(NBDClient *client, uint32_t length)
{
int csock;
NBDExport *exp;

csock = client->sock;
if (length) {
return nbd_send_rep(csock, NBD_REP_ERR_INVALID, NBD_OPT_LIST);
}

/* For each export, send a NBD_REP_SERVER reply. */
QTAILQ_FOREACH(exp, &exports, next) {
if (nbd_send_rep_list(csock, exp)) {
return -EINVAL;
}
}
/* Finish with a NBD_REP_ACK. */
return nbd_send_rep(csock, NBD_REP_ACK, NBD_OPT_LIST);
}

static int nbd_handle_export_name(NBDClient *client, uint32_t length)
{
int rc = -EINVAL, csock = client->sock;
char name[256];

/* Client sends:
[20 .. xx] export name (length bytes)
*/
TRACE("Checking length");
length = be32_to_cpu(length);
if (length > 255) {
LOG("Bad length received");
goto fail;
Expand All @@ -286,13 +335,81 @@ static int nbd_receive_options(NBDClient *client)

QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
nbd_export_get(client->exp);

TRACE("Option negotiation succeeded.");
rc = 0;
fail:
return rc;
}

static int nbd_receive_options(NBDClient *client)
{
while (1) {
int csock = client->sock;
uint32_t tmp, length;
uint64_t magic;

/* Client sends:
[ 0 .. 3] client flags
[ 4 .. 11] NBD_OPTS_MAGIC
[12 .. 15] NBD option
[16 .. 19] length
... Rest of request
*/

if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
LOG("read failed");
return -EINVAL;
}
TRACE("Checking client flags");
tmp = be32_to_cpu(tmp);
if (tmp != 0 && tmp != NBD_FLAG_C_FIXED_NEWSTYLE) {
LOG("Bad client flags received");
return -EINVAL;
}

if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
LOG("read failed");
return -EINVAL;
}
TRACE("Checking opts magic");
if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) {
LOG("Bad magic received");
return -EINVAL;
}

if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
LOG("read failed");
return -EINVAL;
}

if (read_sync(csock, &length, sizeof(length)) != sizeof(length)) {
LOG("read failed");
return -EINVAL;
}
length = be32_to_cpu(length);

TRACE("Checking option");
switch (be32_to_cpu(tmp)) {
case NBD_OPT_LIST:
if (nbd_handle_list(client, length) < 0) {
return 1;
}
break;

case NBD_OPT_ABORT:
return -EINVAL;

case NBD_OPT_EXPORT_NAME:
return nbd_handle_export_name(client, length);

default:
tmp = be32_to_cpu(tmp);
LOG("Unsupported option 0x%x", tmp);
nbd_send_rep(client->sock, NBD_REP_ERR_UNSUP, tmp);
return -EINVAL;
}
}
}

static int nbd_send_negotiate(NBDClient *client)
{
int csock = client->sock;
Expand Down Expand Up @@ -333,6 +450,7 @@ static int nbd_send_negotiate(NBDClient *client)
cpu_to_be16w((uint16_t*)(buf + 26), client->exp->nbdflags | myflags);
} else {
cpu_to_be64w((uint64_t*)(buf + 8), NBD_OPTS_MAGIC);
cpu_to_be16w((uint16_t *)(buf + 16), NBD_FLAG_FIXED_NEWSTYLE);
}

if (client->exp) {
Expand All @@ -346,7 +464,7 @@ static int nbd_send_negotiate(NBDClient *client)
goto fail;
}
rc = nbd_receive_options(client);
if (rc < 0) {
if (rc != 0) {
LOG("option negotiation failed");
goto fail;
}
Expand Down Expand Up @@ -1001,6 +1119,7 @@ static void nbd_trip(void *opaque)
struct nbd_request request;
struct nbd_reply reply;
ssize_t ret;
uint32_t command;

TRACE("Reading request.");
if (client->closing) {
Expand All @@ -1023,8 +1142,8 @@ static void nbd_trip(void *opaque)
reply.error = -ret;
goto error_reply;
}

if ((request.from + request.len) > exp->size) {
command = request.type & NBD_CMD_MASK_COMMAND;
if (command != NBD_CMD_DISC && (request.from + request.len) > exp->size) {
LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
", Offset: %" PRIu64 "\n",
request.from, request.len,
Expand All @@ -1033,7 +1152,7 @@ static void nbd_trip(void *opaque)
goto invalid_request;
}

switch (request.type & NBD_CMD_MASK_COMMAND) {
switch (command) {
case NBD_CMD_READ:
TRACE("Request type is READ");

Expand Down Expand Up @@ -1173,7 +1292,7 @@ NBDClient *nbd_client_new(NBDExport *exp, int csock,
client->refcount = 1;
client->exp = exp;
client->sock = csock;
if (nbd_send_negotiate(client) < 0) {
if (nbd_send_negotiate(client)) {
g_free(client);
return NULL;
}
Expand Down
1 change: 1 addition & 0 deletions qemu-nbd.c
View file
Expand Up @@ -372,6 +372,7 @@ static void nbd_accept(void *opaque)
if (nbd_client_new(exp, fd, nbd_client_closed)) {
nb_fds++;
} else {
shutdown(fd, 2);
close(fd);
}
}
Expand Down

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