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authorEric Blake <eblake@redhat.com>2017-07-07 15:30:46 -0500
committerPaolo Bonzini <pbonzini@redhat.com>2017-07-14 12:04:42 +0200
commitf37708f6b8e0bef0dd85c6aad7fc2062071f8227 (patch)
tree5d12f5e01624f077d8a86ca81aca2c8a68f821ba
parent23e099c34c6c5d774af37be8f7b57a9e563c58f4 (diff)
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nbd: Implement NBD_OPT_GO on server
NBD_OPT_EXPORT_NAME is lousy: per the NBD protocol, any failure requires us to close the connection rather than report an error. Therefore, upstream NBD recently added NBD_OPT_GO as the improved version of the option that does what we want [1], along with NBD_OPT_INFO that returns the same information but does not transition to transmission phase. [1] https://github.com/NetworkBlockDevice/nbd/blob/extension-info/doc/proto.md This is a first cut at the information types, and only passes the same information already available through NBD_OPT_LIST and NBD_OPT_EXPORT_NAME; items like NBD_INFO_BLOCK_SIZE (and thus any use of NBD_REP_ERR_BLOCK_SIZE_REQD) are intentionally left for later patches. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20170707203049.534-7-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--nbd/server.c179
-rw-r--r--nbd/trace-events3
2 files changed, 179 insertions, 3 deletions
diff --git a/nbd/server.c b/nbd/server.c
index 841986d..e84d012 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -141,6 +141,7 @@ static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type,
trace_nbd_negotiate_send_rep_len(opt, nbd_opt_lookup(opt),
type, nbd_rep_lookup(type), len);
+ assert(len < NBD_MAX_BUFFER_SIZE);
magic = cpu_to_be64(NBD_REP_MAGIC);
if (nbd_write(ioc, &magic, sizeof(magic), errp) < 0) {
error_prepend(errp, "write failed (rep magic): ");
@@ -275,6 +276,8 @@ static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length,
return nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_LIST, errp);
}
+/* Send a reply to NBD_OPT_EXPORT_NAME.
+ * Return -errno on error, 0 on success. */
static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length,
uint16_t myflags, bool no_zeroes,
Error **errp)
@@ -323,6 +326,162 @@ static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length,
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 int nbd_negotiate_send_info(NBDClient *client, uint32_t opt,
+ 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->ioc, NBD_REP_INFO, opt,
+ sizeof(info) + length, errp);
+ if (rc < 0) {
+ return rc;
+ }
+ cpu_to_be16s(&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;
+}
+
+/* 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 int nbd_negotiate_handle_info(NBDClient *client, uint32_t length,
+ uint32_t opt, uint16_t myflags,
+ Error **errp)
+{
+ int rc;
+ char name[NBD_MAX_NAME_SIZE + 1];
+ NBDExport *exp;
+ uint16_t requests;
+ uint16_t request;
+ uint32_t namelen;
+ bool sendname = false;
+ char buf[sizeof(uint64_t) + sizeof(uint16_t)];
+ const char *msg;
+
+ /* 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
+ */
+ if (length < sizeof(namelen) + sizeof(requests)) {
+ msg = "overall request too short";
+ goto invalid;
+ }
+ if (nbd_read(client->ioc, &namelen, sizeof(namelen), errp) < 0) {
+ return -EIO;
+ }
+ be32_to_cpus(&namelen);
+ length -= sizeof(namelen);
+ if (namelen > length - sizeof(requests) || (length - namelen) % 2) {
+ msg = "name length is incorrect";
+ goto invalid;
+ }
+ if (nbd_read(client->ioc, name, namelen, errp) < 0) {
+ return -EIO;
+ }
+ name[namelen] = '\0';
+ length -= namelen;
+ trace_nbd_negotiate_handle_export_name_request(name);
+
+ if (nbd_read(client->ioc, &requests, sizeof(requests), errp) < 0) {
+ return -EIO;
+ }
+ be16_to_cpus(&requests);
+ length -= sizeof(requests);
+ trace_nbd_negotiate_handle_info_requests(requests);
+ if (requests != length / sizeof(request)) {
+ msg = "incorrect number of requests for overall length";
+ goto invalid;
+ }
+ while (requests--) {
+ if (nbd_read(client->ioc, &request, sizeof(request), errp) < 0) {
+ return -EIO;
+ }
+ be16_to_cpus(&request);
+ length -= sizeof(request);
+ trace_nbd_negotiate_handle_info_request(request,
+ nbd_info_lookup(request));
+ /* For now, we only care about NBD_INFO_NAME; everything else
+ * is either a request we don't know or something we send
+ * regardless of request. */
+ if (request == NBD_INFO_NAME) {
+ sendname = true;
+ }
+ }
+
+ exp = nbd_export_find(name);
+ if (!exp) {
+ return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_UNKNOWN,
+ opt, errp, "export '%s' not present",
+ name);
+ }
+
+ /* Don't bother sending NBD_INFO_NAME unless client requested it */
+ if (sendname) {
+ rc = nbd_negotiate_send_info(client, opt, NBD_INFO_NAME, length, 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);
+
+ rc = nbd_negotiate_send_info(client, opt, NBD_INFO_DESCRIPTION,
+ len, exp->description, errp);
+ if (rc < 0) {
+ return rc;
+ }
+ }
+
+ /* Send NBD_INFO_EXPORT always */
+ trace_nbd_negotiate_new_style_size_flags(exp->size,
+ exp->nbdflags | myflags);
+ stq_be_p(buf, exp->size);
+ stw_be_p(buf + 8, exp->nbdflags | myflags);
+ rc = nbd_negotiate_send_info(client, opt, NBD_INFO_EXPORT,
+ sizeof(buf), buf, errp);
+ if (rc < 0) {
+ return rc;
+ }
+
+ /* Final reply */
+ rc = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, opt, errp);
+ if (rc < 0) {
+ return rc;
+ }
+
+ if (opt == NBD_OPT_GO) {
+ client->exp = exp;
+ QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
+ nbd_export_get(client->exp);
+ rc = 1;
+ }
+ return rc;
+
+ invalid:
+ if (nbd_drop(client->ioc, length, errp) < 0) {
+ return -EIO;
+ }
+ return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, opt,
+ errp, "%s", msg);
+}
+
+
/* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
* new channel for all further (now-encrypted) communication. */
static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
@@ -380,7 +539,8 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
}
/* nbd_negotiate_options
- * Process all NBD_OPT_* client option commands.
+ * 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
@@ -397,7 +557,7 @@ static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
/* Client sends:
[ 0 .. 3] client flags
- Then we loop until NBD_OPT_EXPORT_NAME:
+ 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
@@ -524,6 +684,19 @@ static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
myflags, no_zeroes,
errp);
+ case NBD_OPT_INFO:
+ case NBD_OPT_GO:
+ ret = nbd_negotiate_handle_info(client, length, option,
+ myflags, errp);
+ if (ret == 1) {
+ assert(option == NBD_OPT_GO);
+ return 0;
+ }
+ if (ret) {
+ return ret;
+ }
+ break;
+
case NBD_OPT_STARTTLS:
if (nbd_drop(client->ioc, length, errp) < 0) {
return -EIO;
@@ -606,7 +779,7 @@ static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
[ 0 .. 7] passwd ("NBDMAGIC")
[ 8 .. 15] magic (NBD_OPTS_MAGIC)
[16 .. 17] server flags (0)
- ....options sent, ending in NBD_OPT_EXPORT_NAME....
+ ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO....
*/
qio_channel_set_blocking(client->ioc, false, NULL);
diff --git a/nbd/trace-events b/nbd/trace-events
index 8db0500..5230c61 100644
--- a/nbd/trace-events
+++ b/nbd/trace-events
@@ -33,6 +33,9 @@ nbd_negotiate_send_rep_err(const char *msg) "sending error message \"%s\""
nbd_negotiate_send_rep_list(const char *name, const char *desc) "Advertising export name '%s' description '%s'"
nbd_negotiate_handle_export_name(void) "Checking length"
nbd_negotiate_handle_export_name_request(const char *name) "Client requested export '%s'"
+nbd_negotiate_send_info(int info, const char *name, uint32_t length) "Sending NBD_REP_INFO type %d (%s) with remaining length %" PRIu32
+nbd_negotiate_handle_info_requests(int requests) "Client requested %d items of info"
+nbd_negotiate_handle_info_request(int request, const char *name) "Client requested info %d (%s)"
nbd_negotiate_handle_starttls(void) "Setting up TLS"
nbd_negotiate_handle_starttls_handshake(void) "Starting TLS handshake"
nbd_negotiate_options_flags(uint32_t flags) "Received client flags 0x%" PRIx32