[Qemu-devel] nbd: Add exports listing support

[Qemu-devel] nbd: Add exports listing support

[Hani Benhabiles]

Before the patches:

$ nbd-client -l localhost
Negotiation: ..
E: Server does not support listing exports

After the patches:
$ nbd-client -l localhost
Negotiation: ..
ide0-hd0
ide1-cd0

Hani Benhabiles (2):
  nbd: Handle fixed new-style clients.
  nbd: Handle NBD_OPT_LIST option.

 include/block/nbd.h |  10 +++++
 nbd.c               | 109 ++++++++++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 112 insertions(+), 7 deletions(-)

-- 
1.8.3.2

[Qemu-devel] [PATCH 1/2] nbd: Handle fixed new-style clients.

[Hani Benhabiles]

Signed-off-by: Hani Benhabiles <hani@linux.com>
---
 include/block/nbd.h |  6 ++++++
 nbd.c               | 12 +++++++-----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/include/block/nbd.h b/include/block/nbd.h
index 79502a0..95d52ab 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -45,6 +45,12 @@ 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. */
+
 #define NBD_CMD_MASK_COMMAND	0x0000ffff
 #define NBD_CMD_FLAG_FUA	(1 << 16)
 
diff --git a/nbd.c b/nbd.c
index e5084b6..fb0a9cf 100644
--- a/nbd.c
+++ b/nbd.c
@@ -224,7 +224,7 @@ static int nbd_receive_options(NBDClient *client)
     int rc;
 
     /* Client sends:
-        [ 0 ..   3]   reserved (0)
+        [ 0 ..   3]   client flags
         [ 4 ..  11]   NBD_OPTS_MAGIC
         [12 ..  15]   NBD_OPT_EXPORT_NAME
         [16 ..  19]   length
@@ -236,9 +236,10 @@ static int nbd_receive_options(NBDClient *client)
         LOG("read failed");
         goto fail;
     }
-    TRACE("Checking reserved");
-    if (tmp != 0) {
-        LOG("Bad reserved received");
+    TRACE("Checking client flags");
+    tmp = be32_to_cpu(tmp);
+    if (tmp != 0 && tmp != NBD_FLAG_C_FIXED_NEWSTYLE) {
+        LOG("Bad client flags received");
         goto fail;
     }
 
@@ -246,7 +247,7 @@ static int nbd_receive_options(NBDClient *client)
         LOG("read failed");
         goto fail;
     }
-    TRACE("Checking reserved");
+    TRACE("Checking opts magic");
     if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) {
         LOG("Bad magic received");
         goto fail;
@@ -333,6 +334,7 @@ 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) {
-- 
1.8.3.2

[Qemu-devel] [PATCH 2/2] nbd: Handle NBD_OPT_LIST option.

[Hani Benhabiles]

Signed-off-by: Hani Benhabiles <hani@linux.com>
---
 include/block/nbd.h |  4 +++
 nbd.c               | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 99 insertions(+), 2 deletions(-)

diff --git a/include/block/nbd.h b/include/block/nbd.h
index 95d52ab..23e9a84 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -51,6 +51,10 @@ struct nbd_reply {
 /* 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_CMD_MASK_COMMAND	0x0000ffff
 #define NBD_CMD_FLAG_FUA	(1 << 16)
 
diff --git a/nbd.c b/nbd.c
index fb0a9cf..9150fa6 100644
--- a/nbd.c
+++ b/nbd.c
@@ -64,6 +64,7 @@
 #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 +78,8 @@
 #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_LIST            (3)
 
 /* Definitions for opaque data types */
 
@@ -215,6 +217,88 @@ static ssize_t write_sync(int fd, void *buffer, size_t size)
 
 */
 
+static int nbd_send_rep_ack(int csock)
+{
+    uint64_t magic;
+    uint32_t opt, type, 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(NBD_OPT_LIST);
+    if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {
+        LOG("write failed (opt list)");
+        return -EINVAL;
+    }
+    type = cpu_to_be32(NBD_REP_ACK);
+    if (write_sync(csock, &type, sizeof(type)) != sizeof(type)) {
+        LOG("write failed (rep ack)");
+        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_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;
+    }
+    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;
+}
+
+static int nbd_send_list(NBDClient *client)
+{
+    int csock;
+    NBDExport *exp;
+
+    csock = client->sock;
+    /* 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_ack(csock);
+}
+
 static int nbd_receive_options(NBDClient *client)
 {
     int csock = client->sock;
@@ -258,6 +342,13 @@ static int nbd_receive_options(NBDClient *client)
         goto fail;
     }
     TRACE("Checking option");
+    if (tmp == be32_to_cpu(NBD_OPT_LIST)) {
+        if (nbd_send_list(client) < 0) {
+            return -EINVAL;
+        } else {
+            return 1;
+        }
+    }
     if (tmp != be32_to_cpu(NBD_OPT_EXPORT_NAME)) {
         LOG("Bad option received");
         goto fail;
@@ -351,6 +442,8 @@ 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);
@@ -1175,7 +1268,7 @@ 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