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[Qemu-devel] [PATCH 1/2] nbd: Handle fixed new-style clients.
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From: |
Hani Benhabiles |
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Subject: |
[Qemu-devel] [PATCH 1/2] nbd: Handle fixed new-style clients. |
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Date: |
Sat, 7 Jun 2014 01:32:31 +0100 |
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 <address@hidden>
---
include/block/nbd.h | 9 ++++
nbd.c | 143 ++++++++++++++++++++++++++++++++++++----------------
2 files changed, 109 insertions(+), 43 deletions(-)
diff --git a/include/block/nbd.h b/include/block/nbd.h
index 79502a0..561b70c 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -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)
diff --git a/nbd.c b/nbd.c
index e0d032c..7cee1ef 100644
--- a/nbd.c
+++ b/nbd.c
@@ -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 */
@@ -215,53 +221,44 @@ 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;
- }
- TRACE("Checking option");
- if (tmp != be32_to_cpu(NBD_OPT_EXPORT_NAME)) {
- LOG("Bad option received");
- goto fail;
- }
+static int nbd_handle_export_name(NBDClient *client)
+{
+ int rc = -EINVAL, csock = client->sock;
+ char name[256];
+ uint32_t length;
+ /* Client sends:
+ [16 .. 19] length
+ [20 .. xx] export name (length bytes)
+ */
if (read_sync(csock, &length, sizeof(length)) != sizeof(length)) {
LOG("read failed");
goto fail;
@@ -286,13 +283,70 @@ 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;
+ uint64_t magic;
+
+ /* Client sends:
+ [ 0 .. 3] client flags
+ [ 4 .. 11] NBD_OPTS_MAGIC
+ [12 .. 15] NBD option
+ ... 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;
+ }
+
+ TRACE("Checking option");
+ switch (be32_to_cpu(tmp)) {
+ case NBD_OPT_ABORT:
+ return 1;
+
+ case NBD_OPT_EXPORT_NAME:
+ return nbd_handle_export_name(client);
+
+ default:
+ tmp = be32_to_cpu(tmp);
+ LOG("Unsupported option 0x%x", tmp);
+ if (nbd_send_rep(client->sock, NBD_REP_ERR_UNSUP, tmp)) {
+ return -EINVAL;
+ }
+ return 1;
+ }
+ }
+}
+
static int nbd_send_negotiate(NBDClient *client)
{
int csock = client->sock;
@@ -333,6 +387,7 @@ 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) {
@@ -349,6 +404,8 @@ static int nbd_send_negotiate(NBDClient *client)
if (rc < 0) {
LOG("option negotiation failed");
goto fail;
+ } else if (rc > 0) {
+ goto fail;
}
assert ((client->exp->nbdflags & ~65535) == 0);
@@ -1173,7 +1230,7 @@ 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;
}
--
1.8.3.2