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-rw-r--r--block/monitor/block-hmp-cmds.c3
-rw-r--r--blockdev-nbd.c47
-rw-r--r--include/block/nbd.h18
-rw-r--r--nbd/server.c48
-rw-r--r--nbd/trace-events1
-rw-r--r--qapi/block-export.json4
-rw-r--r--qemu-nbd.c7
7 files changed, 116 insertions, 12 deletions
diff --git a/block/monitor/block-hmp-cmds.c b/block/monitor/block-hmp-cmds.c
index d954bec..bdf2eb5 100644
--- a/block/monitor/block-hmp-cmds.c
+++ b/block/monitor/block-hmp-cmds.c
@@ -402,7 +402,8 @@ void hmp_nbd_server_start(Monitor *mon, const QDict *qdict)
goto exit;
}
- nbd_server_start(addr, NULL, NULL, 0, &local_err);
+ nbd_server_start(addr, NULL, NULL, NBD_DEFAULT_MAX_CONNECTIONS,
+ &local_err);
qapi_free_SocketAddress(addr);
if (local_err != NULL) {
goto exit;
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index 2130124..f73409a 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -21,12 +21,18 @@
#include "io/channel-socket.h"
#include "io/net-listener.h"
+typedef struct NBDConn {
+ QIOChannelSocket *cioc;
+ QLIST_ENTRY(NBDConn) next;
+} NBDConn;
+
typedef struct NBDServerData {
QIONetListener *listener;
QCryptoTLSCreds *tlscreds;
char *tlsauthz;
uint32_t max_connections;
uint32_t connections;
+ QLIST_HEAD(, NBDConn) conns;
} NBDServerData;
static NBDServerData *nbd_server;
@@ -51,6 +57,14 @@ int nbd_server_max_connections(void)
static void nbd_blockdev_client_closed(NBDClient *client, bool ignored)
{
+ NBDConn *conn = nbd_client_owner(client);
+
+ assert(qemu_in_main_thread() && nbd_server);
+
+ object_unref(OBJECT(conn->cioc));
+ QLIST_REMOVE(conn, next);
+ g_free(conn);
+
nbd_client_put(client);
assert(nbd_server->connections > 0);
nbd_server->connections--;
@@ -60,12 +74,20 @@ static void nbd_blockdev_client_closed(NBDClient *client, bool ignored)
static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
gpointer opaque)
{
+ NBDConn *conn = g_new0(NBDConn, 1);
+
+ assert(qemu_in_main_thread() && nbd_server);
nbd_server->connections++;
+ object_ref(OBJECT(cioc));
+ conn->cioc = cioc;
+ QLIST_INSERT_HEAD(&nbd_server->conns, conn, next);
nbd_update_server_watch(nbd_server);
qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server");
- nbd_client_new(cioc, nbd_server->tlscreds, nbd_server->tlsauthz,
- nbd_blockdev_client_closed);
+ /* TODO - expose handshake timeout as QMP option */
+ nbd_client_new(cioc, NBD_DEFAULT_HANDSHAKE_MAX_SECS,
+ nbd_server->tlscreds, nbd_server->tlsauthz,
+ nbd_blockdev_client_closed, conn);
}
static void nbd_update_server_watch(NBDServerData *s)
@@ -79,12 +101,25 @@ static void nbd_update_server_watch(NBDServerData *s)
static void nbd_server_free(NBDServerData *server)
{
+ NBDConn *conn, *tmp;
+
if (!server) {
return;
}
+ /*
+ * Forcefully close the listener socket, and any clients that have
+ * not yet disconnected on their own.
+ */
qio_net_listener_disconnect(server->listener);
object_unref(OBJECT(server->listener));
+ QLIST_FOREACH_SAFE(conn, &server->conns, next, tmp) {
+ qio_channel_shutdown(QIO_CHANNEL(conn->cioc), QIO_CHANNEL_SHUTDOWN_BOTH,
+ NULL);
+ }
+
+ AIO_WAIT_WHILE_UNLOCKED(NULL, server->connections > 0);
+
if (server->tlscreds) {
object_unref(OBJECT(server->tlscreds));
}
@@ -168,6 +203,10 @@ void nbd_server_start(SocketAddress *addr, const char *tls_creds,
void nbd_server_start_options(NbdServerOptions *arg, Error **errp)
{
+ if (!arg->has_max_connections) {
+ arg->max_connections = NBD_DEFAULT_MAX_CONNECTIONS;
+ }
+
nbd_server_start(arg->addr, arg->tls_creds, arg->tls_authz,
arg->max_connections, errp);
}
@@ -180,6 +219,10 @@ void qmp_nbd_server_start(SocketAddressLegacy *addr,
{
SocketAddress *addr_flat = socket_address_flatten(addr);
+ if (!has_max_connections) {
+ max_connections = NBD_DEFAULT_MAX_CONNECTIONS;
+ }
+
nbd_server_start(addr_flat, tls_creds, tls_authz, max_connections, errp);
qapi_free_SocketAddress(addr_flat);
}
diff --git a/include/block/nbd.h b/include/block/nbd.h
index 4e7bd63..d4f8b21 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -33,6 +33,19 @@ typedef struct NBDMetaContexts NBDMetaContexts;
extern const BlockExportDriver blk_exp_nbd;
+/*
+ * NBD_DEFAULT_HANDSHAKE_MAX_SECS: Number of seconds in which client must
+ * succeed at NBD_OPT_GO before being forcefully dropped as too slow.
+ */
+#define NBD_DEFAULT_HANDSHAKE_MAX_SECS 10
+
+/*
+ * NBD_DEFAULT_MAX_CONNECTIONS: Number of client sockets to allow at
+ * once; must be large enough to allow a MULTI_CONN-aware client like
+ * nbdcopy to create its typical number of 8-16 sockets.
+ */
+#define NBD_DEFAULT_MAX_CONNECTIONS 100
+
/* Handshake phase structs - this struct is passed on the wire */
typedef struct NBDOption {
@@ -403,9 +416,12 @@ AioContext *nbd_export_aio_context(NBDExport *exp);
NBDExport *nbd_export_find(const char *name);
void nbd_client_new(QIOChannelSocket *sioc,
+ uint32_t handshake_max_secs,
QCryptoTLSCreds *tlscreds,
const char *tlsauthz,
- void (*close_fn)(NBDClient *, bool));
+ void (*close_fn)(NBDClient *, bool),
+ void *owner);
+void *nbd_client_owner(NBDClient *client);
void nbd_client_get(NBDClient *client);
void nbd_client_put(NBDClient *client);
diff --git a/nbd/server.c b/nbd/server.c
index 892797b..c30e687 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -124,12 +124,14 @@ struct NBDMetaContexts {
struct NBDClient {
int refcount; /* atomic */
void (*close_fn)(NBDClient *client, bool negotiated);
+ void *owner;
QemuMutex lock;
NBDExport *exp;
QCryptoTLSCreds *tlscreds;
char *tlsauthz;
+ uint32_t handshake_max_secs;
QIOChannelSocket *sioc; /* The underlying data channel */
QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
@@ -1972,7 +1974,7 @@ static void nbd_export_request_shutdown(BlockExport *blk_exp)
blk_exp_ref(&exp->common);
/*
- * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a
+ * TODO: Should we expand QMP BlockExportRemoveMode enum to allow a
* close mode that stops advertising the export to new clients but
* still permits existing clients to run to completion? Because of
* that possibility, nbd_export_close() can be called more than
@@ -3184,35 +3186,65 @@ static void nbd_client_receive_next_request(NBDClient *client)
}
}
+static void nbd_handshake_timer_cb(void *opaque)
+{
+ QIOChannel *ioc = opaque;
+
+ trace_nbd_handshake_timer_cb();
+ qio_channel_shutdown(ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
+}
+
static coroutine_fn void nbd_co_client_start(void *opaque)
{
NBDClient *client = opaque;
Error *local_err = NULL;
+ QEMUTimer *handshake_timer = NULL;
qemu_co_mutex_init(&client->send_lock);
+ /*
+ * Create a timer to bound the time spent in negotiation. If the
+ * timer expires, it is likely nbd_negotiate will fail because the
+ * socket was shutdown.
+ */
+ if (client->handshake_max_secs > 0) {
+ handshake_timer = aio_timer_new(qemu_get_aio_context(),
+ QEMU_CLOCK_REALTIME,
+ SCALE_NS,
+ nbd_handshake_timer_cb,
+ client->sioc);
+ timer_mod(handshake_timer,
+ qemu_clock_get_ns(QEMU_CLOCK_REALTIME) +
+ client->handshake_max_secs * NANOSECONDS_PER_SECOND);
+ }
+
if (nbd_negotiate(client, &local_err)) {
if (local_err) {
error_report_err(local_err);
}
+ timer_free(handshake_timer);
client_close(client, false);
return;
}
+ timer_free(handshake_timer);
WITH_QEMU_LOCK_GUARD(&client->lock) {
nbd_client_receive_next_request(client);
}
}
/*
- * Create a new client listener using the given channel @sioc.
+ * Create a new client listener using the given channel @sioc and @owner.
* Begin servicing it in a coroutine. When the connection closes, call
- * @close_fn with an indication of whether the client completed negotiation.
+ * @close_fn with an indication of whether the client completed negotiation
+ * within @handshake_max_secs seconds (0 for unbounded).
*/
void nbd_client_new(QIOChannelSocket *sioc,
+ uint32_t handshake_max_secs,
QCryptoTLSCreds *tlscreds,
const char *tlsauthz,
- void (*close_fn)(NBDClient *, bool))
+ void (*close_fn)(NBDClient *, bool),
+ void *owner)
{
NBDClient *client;
Coroutine *co;
@@ -3225,13 +3257,21 @@ void nbd_client_new(QIOChannelSocket *sioc,
object_ref(OBJECT(client->tlscreds));
}
client->tlsauthz = g_strdup(tlsauthz);
+ client->handshake_max_secs = handshake_max_secs;
client->sioc = sioc;
qio_channel_set_delay(QIO_CHANNEL(sioc), false);
object_ref(OBJECT(client->sioc));
client->ioc = QIO_CHANNEL(sioc);
object_ref(OBJECT(client->ioc));
client->close_fn = close_fn;
+ client->owner = owner;
co = qemu_coroutine_create(nbd_co_client_start, client);
qemu_coroutine_enter(co);
}
+
+void *
+nbd_client_owner(NBDClient *client)
+{
+ return client->owner;
+}
diff --git a/nbd/trace-events b/nbd/trace-events
index 00ae321..cbd0a4a 100644
--- a/nbd/trace-events
+++ b/nbd/trace-events
@@ -76,6 +76,7 @@ nbd_co_receive_request_payload_received(uint64_t cookie, uint64_t len) "Payload
nbd_co_receive_ext_payload_compliance(uint64_t from, uint64_t len) "client sent non-compliant write without payload flag: from=0x%" PRIx64 ", len=0x%" PRIx64
nbd_co_receive_align_compliance(const char *op, uint64_t from, uint64_t len, uint32_t align) "client sent non-compliant unaligned %s request: from=0x%" PRIx64 ", len=0x%" PRIx64 ", align=0x%" PRIx32
nbd_trip(void) "Reading request"
+nbd_handshake_timer_cb(void) "client took too long to negotiate"
# client-connection.c
nbd_connect_thread_sleep(uint64_t timeout) "timeout %" PRIu64
diff --git a/qapi/block-export.json b/qapi/block-export.json
index 665d5fd..ce33fe3 100644
--- a/qapi/block-export.json
+++ b/qapi/block-export.json
@@ -28,7 +28,7 @@
# @max-connections: The maximum number of connections to allow at the
# same time, 0 for unlimited. Setting this to 1 also stops the
# server from advertising multiple client support (since 5.2;
-# default: 0)
+# default: 100)
#
# Since: 4.2
##
@@ -63,7 +63,7 @@
# @max-connections: The maximum number of connections to allow at the
# same time, 0 for unlimited. Setting this to 1 also stops the
# server from advertising multiple client support (since 5.2;
-# default: 0).
+# default: 100).
#
# Errors:
# - if the server is already running
diff --git a/qemu-nbd.c b/qemu-nbd.c
index d7b3cca..a186d2e 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -390,7 +390,9 @@ static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
nb_fds++;
nbd_update_server_watch();
- nbd_client_new(cioc, tlscreds, tlsauthz, nbd_client_closed);
+ /* TODO - expose handshake timeout as command line option */
+ nbd_client_new(cioc, NBD_DEFAULT_HANDSHAKE_MAX_SECS,
+ tlscreds, tlsauthz, nbd_client_closed, NULL);
}
static void nbd_update_server_watch(void)
@@ -588,7 +590,8 @@ int main(int argc, char **argv)
pthread_t client_thread;
const char *fmt = NULL;
Error *local_err = NULL;
- BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
+ BlockdevDetectZeroesOptions detect_zeroes =
+ BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
QDict *options = NULL;
const char *export_name = NULL; /* defaults to "" later for server mode */
const char *export_description = NULL;
generated by cgit v1.1 at 2024-08-10 21:19:53 +0000