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nbd: Handle fixed new-style clients. 

When this flag is set, the server tells the client that it can send another
option if the server received a request with an option that it doesn't
understand instead of directly closing the connection.

Also add link to the most up-to-date documentation.

Signed-off-by: Hani Benhabiles <kroosec@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Hani Benhabiles 2014-06-07 01:32:31 +01:00 committed by Paolo Bonzini
parent 27e5eae457
commit f5076b5a75
2 changed files with 114 additions and 52 deletions
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9
include/block/nbd.h
View File

@ -45,6 +45,15 @@ 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_ERR_UNSUP ((1 << 31) | 1) /* Unknown option. */
#define NBD_CMD_MASK_COMMAND 0x0000ffff
#define NBD_CMD_FLAG_FUA (1 << 16)

157
nbd.c
View File

@ -56,7 +56,11 @@
__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)
@ -64,6 +68,7 @@
#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)
@ -77,7 +82,8 @@
#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)
/* Definitions for opaque data types */
@ -215,59 +221,43 @@ 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;
magic = cpu_to_be64(NBD_REP_MAGIC);
if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
LOG("write failed (rep magic)");
return -EINVAL;
}
opt = cpu_to_be32(opt);
if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
LOG("write failed (rep opt)");
return -EINVAL;
}
type = cpu_to_be32(type);
if (write_sync(csock, &type, sizeof(type)) != sizeof(type)) {
LOG("write failed (rep type)");
return -EINVAL;
}
len = cpu_to_be32(0);
if (write_sync(csock, &len, sizeof(len)) != sizeof(len)) {
LOG("write failed (rep data length)");
return -EINVAL;
}
return 0;
}
static int nbd_handle_export_name(NBDClient *client, uint32_t length)
{
int rc = -EINVAL, csock = client->sock;
char name[256];
/* 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;
}
TRACE("Checking reserved");
if (tmp != 0) {
LOG("Bad reserved received");
goto fail;
}
if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {
LOG("read failed");
goto fail;
}
TRACE("Checking reserved");
if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) {
LOG("Bad magic received");
goto fail;
}
if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {
LOG("read failed");
goto fail;
}
TRACE("Checking option");
if (tmp != be32_to_cpu(NBD_OPT_EXPORT_NAME)) {
LOG("Bad option received");
goto fail;
}
if (read_sync(csock, &length, sizeof(length)) != sizeof(length)) {
LOG("read failed");
goto fail;
}
TRACE("Checking length");
length = be32_to_cpu(length);
if (length > 255) {
LOG("Bad length received");
goto fail;
@ -286,13 +276,75 @@ 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_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;
@ -333,6 +385,7 @@ 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) {
@ -346,7 +399,7 @@ 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;
}
@ -1174,7 +1227,7 @@ 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;
}