[libvirt] [PATCH 3/4] event: wire up RPC for server-side network event filtering

Eric Blake eblake at redhat.com
Wed Jan 15 22:57:37 UTC 2014


We haven't had a release with network events yet, so we are free
to fix the RPC so that it actually does what we want.  Doing
client-side filtering of per-network events is inefficient if a
connection is only interested in events on a single network out
of hundreds available on the server.  But to do server-side
per-network filtering, the server needs to know which network
to filter on - so we need to pass an optional network over on
registration.  Furthermore, it is possible to have a client with
both a global and per-network filter; in the existing code, the
server sends only one event and the client replicates to both
callbacks.  But with server-side filtering, the server will send
the event twice, so we need a way for the client to know which
callbackID is sending an event, to ensure that the client can
filter out events from a registration that does not match the
callbackID from the server.  Likewise, the existing style of
deregistering by eventID alone is fine; but in the new style,
we have to remember which callbackID to delete.

This patch fixes the RPC wire definition to contain all the
needed pieces of information, and hooks into the server and
client side improvements of the previous patches, in order to
switch over to full server-side filtering of network events.
Also, since we fixed this in time, all released versions of
libvirtd that support network events also support per-network
filtering, so we can hard-code that assumption into
network_event.c.

Converting domain events to server-side filtering will require
the introduction of new RPC numbers, as well as a server
feature bit that the client can use to tell whether to use
old-style (server only supports global events) or new-style
(server supports filtered events), so that is deferred to a
later set of patches.

* src/conf/network_event.c (virNetworkEventStateRegisterClient):
Assume server-side filtering.
* src/remote/remote_protocol.x
(remote_connect_network_event_register_any_args): Add network
argument.
(remote_connect_network_event_register_any_ret): Return callbackID
instead of count.
(remote_connect_network_event_deregister_any_args): Pass
callbackID instead of eventID.
(remote_connect_network_event_deregister_any_ret): Drop unused
type.
(remote_network_event_lifecycle_msg): Add callbackID.
* daemon/remote.c
(remoteDispatchConnectNetworkEventDeregisterAny): Drop unused arg,
and deal with callbackID from client.
(remoteRelayNetworkEventLifecycle): Pass callbackID.
(remoteDispatchConnectNetworkEventRegisterAny): Likewise, and
recognize non-NULL network.
* src/remote/remote_driver.c
(remoteConnectNetworkEventRegisterAny): Pass network, and track
server side id.
(remoteConnectNetworkEventDeregisterAny): Deregister by callback id.
(remoteNetworkBuildEventLifecycle): Pass remote id to event queue.
* src/remote_protocol-structs: Regenerate.

Signed-off-by: Eric Blake <eblake at redhat.com>
---
 daemon/remote.c              | 34 +++++++++++++++++-----------------
 src/conf/network_event.c     |  4 +---
 src/remote/remote_driver.c   | 17 ++++++++++++++---
 src/remote/remote_protocol.x | 12 +++++-------
 src/remote_protocol-structs  |  9 ++++-----
 5 files changed, 41 insertions(+), 35 deletions(-)

diff --git a/daemon/remote.c b/daemon/remote.c
index ae318b2..d2aafbe 100644
--- a/daemon/remote.c
+++ b/daemon/remote.c
@@ -685,6 +685,7 @@ remoteRelayNetworkEventLifecycle(virConnectPtr conn ATTRIBUTE_UNUSED,
     /* build return data */
     memset(&data, 0, sizeof(data));
     make_nonnull_network(&data.net, net);
+    data.callbackID = callback->callbackID;
     data.event = event;
     data.detail = detail;

@@ -5285,7 +5286,7 @@ remoteDispatchConnectNetworkEventRegisterAny(virNetServerPtr server ATTRIBUTE_UN
                                              virNetMessagePtr msg ATTRIBUTE_UNUSED,
                                              virNetMessageErrorPtr rerr ATTRIBUTE_UNUSED,
                                              remote_connect_network_event_register_any_args *args,
-                                             remote_connect_network_event_register_any_ret *ret ATTRIBUTE_UNUSED)
+                                             remote_connect_network_event_register_any_ret *ret)
 {
     int callbackID;
     int rv = -1;
@@ -5293,6 +5294,7 @@ remoteDispatchConnectNetworkEventRegisterAny(virNetServerPtr server ATTRIBUTE_UN
     daemonClientEventCallbackPtr ref;
     struct daemonClientPrivate *priv =
         virNetServerClientGetPrivateData(client);
+    virNetworkPtr net = NULL;

     if (!priv->conn) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("connection not open"));
@@ -5301,6 +5303,10 @@ remoteDispatchConnectNetworkEventRegisterAny(virNetServerPtr server ATTRIBUTE_UN

     virMutexLock(&priv->lock);

+    if (args->net &&
+        !(net = get_nonnull_network(priv->conn, *args->net)))
+        goto cleanup;
+
     if (args->eventID >= VIR_NETWORK_EVENT_ID_LAST || args->eventID < 0) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
                        _("unsupported network event ID %d"), args->eventID);
@@ -5325,7 +5331,7 @@ remoteDispatchConnectNetworkEventRegisterAny(virNetServerPtr server ATTRIBUTE_UN
         goto cleanup;

     if ((callbackID = virConnectNetworkEventRegisterAny(priv->conn,
-                                                        NULL,
+                                                        net,
                                                         args->eventID,
                                                         networkEventCallbacks[args->eventID],
                                                         ref,
@@ -5337,6 +5343,7 @@ remoteDispatchConnectNetworkEventRegisterAny(virNetServerPtr server ATTRIBUTE_UN
     }

     ref->callbackID = callbackID;
+    ret->callbackID = callbackID;

     rv = 0;

@@ -5344,6 +5351,8 @@ cleanup:
     VIR_FREE(callback);
     if (rv < 0)
         virNetMessageSaveError(rerr);
+    if (net)
+        virNetworkFree(net);
     virMutexUnlock(&priv->lock);
     return rv;
 }
@@ -5354,10 +5363,8 @@ remoteDispatchConnectNetworkEventDeregisterAny(virNetServerPtr server ATTRIBUTE_
                                                virNetServerClientPtr client,
                                                virNetMessagePtr msg ATTRIBUTE_UNUSED,
                                                virNetMessageErrorPtr rerr ATTRIBUTE_UNUSED,
-                                               remote_connect_network_event_deregister_any_args *args,
-                                               remote_connect_network_event_deregister_any_ret *ret ATTRIBUTE_UNUSED)
+                                               remote_connect_network_event_deregister_any_args *args)
 {
-    int callbackID = -1;
     int rv = -1;
     size_t i;
     struct daemonClientPrivate *priv =
@@ -5370,25 +5377,18 @@ remoteDispatchConnectNetworkEventDeregisterAny(virNetServerPtr server ATTRIBUTE_

     virMutexLock(&priv->lock);

-    if (args->eventID >= VIR_NETWORK_EVENT_ID_LAST || args->eventID < 0) {
-        virReportError(VIR_ERR_INTERNAL_ERROR,
-                       _("unsupported event ID %d"), args->eventID);
-        goto cleanup;
-    }
-
     for (i = 0; i < priv->nnetworkEventCallbacks; i++) {
-        if (priv->networkEventCallbacks[i]->eventID == args->eventID) {
-            callbackID = priv->networkEventCallbacks[i]->callbackID;
+        if (priv->networkEventCallbacks[i]->callbackID == args->callbackID)
             break;
-        }
     }
-    if (callbackID < 0) {
+    if (i == priv->nnetworkEventCallbacks) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
-                       _("network event %d not registered"), args->eventID);
+                       _("network event callback %d not registered"),
+                       args->callbackID);
         goto cleanup;
     }

-    if (virConnectNetworkEventDeregisterAny(priv->conn, callbackID) < 0)
+    if (virConnectNetworkEventDeregisterAny(priv->conn, args->callbackID) < 0)
         goto cleanup;

     VIR_DELETE_ELEMENT(priv->networkEventCallbacks, i,
diff --git a/src/conf/network_event.c b/src/conf/network_event.c
index d9c47b8..a0b60a0 100644
--- a/src/conf/network_event.c
+++ b/src/conf/network_event.c
@@ -189,12 +189,10 @@ virNetworkEventStateRegisterClient(virConnectPtr conn,
     if (virNetworkEventsInitialize() < 0)
         return -1;

-    /* FIXME: All servers that support network events should also support
-     * per-object filtering.  */
     return virObjectEventStateRegisterID(conn, state, net ? net->uuid : NULL,
                                          virNetworkEventClass, eventID,
                                          VIR_OBJECT_EVENT_CALLBACK(cb),
-                                         opaque, freecb, callbackID, false);
+                                         opaque, freecb, callbackID, true);
 }


diff --git a/src/remote/remote_driver.c b/src/remote/remote_driver.c
index d719a49..18eb454 100644
--- a/src/remote/remote_driver.c
+++ b/src/remote/remote_driver.c
@@ -2923,8 +2923,10 @@ remoteConnectNetworkEventRegisterAny(virConnectPtr conn,
     int rv = -1;
     struct private_data *priv = conn->privateData;
     remote_connect_network_event_register_any_args args;
+    remote_connect_network_event_register_any_ret ret;
     int callbackID;
     int count;
+    remote_nonnull_network network;

     remoteDriverLock(priv);

@@ -2938,14 +2940,23 @@ remoteConnectNetworkEventRegisterAny(virConnectPtr conn,
      * events on the server */
     if (count == 1) {
         args.eventID = eventID;
+        if (net) {
+            make_nonnull_network(&network, net);
+            args.net = &network;
+        } else {
+            args.net = NULL;
+        }

+        memset(&ret, 0, sizeof(ret));
         if (call(conn, priv, 0, REMOTE_PROC_CONNECT_NETWORK_EVENT_REGISTER_ANY,
                  (xdrproc_t) xdr_remote_connect_network_event_register_any_args, (char *) &args,
-                 (xdrproc_t) xdr_void, (char *)NULL) == -1) {
+                 (xdrproc_t) xdr_remote_connect_network_event_register_any_ret, (char *) &ret) == -1) {
             virObjectEventStateDeregisterID(conn, priv->eventState,
                                             callbackID);
             goto done;
         }
+        virObjectEventStateSetRemote(conn, priv->eventState, callbackID,
+                                     ret.callbackID);
     }

     rv = callbackID;
@@ -2980,7 +2991,7 @@ remoteConnectNetworkEventDeregisterAny(virConnectPtr conn,
     /* If that was the last callback for this eventID, we need to disable
      * events on the server */
     if (count == 0) {
-        args.eventID = eventID;
+        args.callbackID = remoteID;

         if (call(conn, priv, 0, REMOTE_PROC_CONNECT_NETWORK_EVENT_DEREGISTER_ANY,
                  (xdrproc_t) xdr_remote_connect_network_event_deregister_any_args, (char *) &args,
@@ -4924,7 +4935,7 @@ remoteNetworkBuildEventLifecycle(virNetClientProgramPtr prog ATTRIBUTE_UNUSED,
                                         msg->detail);
     virNetworkFree(net);

-    remoteEventQueue(priv, event, -1);
+    remoteEventQueue(priv, event, msg->callbackID);
 }


diff --git a/src/remote/remote_protocol.x b/src/remote/remote_protocol.x
index c3d544f..ae27a77 100644
--- a/src/remote/remote_protocol.x
+++ b/src/remote/remote_protocol.x
@@ -3,7 +3,7 @@
  *   remote_internal driver and libvirtd.  This protocol is
  *   internal and may change at any time.
  *
- * Copyright (C) 2006-2013 Red Hat, Inc.
+ * Copyright (C) 2006-2014 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -2851,21 +2851,19 @@ struct remote_connect_get_cpu_model_names_ret {

 struct remote_connect_network_event_register_any_args {
     int eventID;
+    remote_network net;
 };

 struct remote_connect_network_event_register_any_ret {
-    int cb_registered;
+    int callbackID;
 };

 struct remote_connect_network_event_deregister_any_args {
-    int eventID;
-};
-
-struct remote_connect_network_event_deregister_any_ret {
-    int cb_registered;
+    int callbackID;
 };

 struct remote_network_event_lifecycle_msg {
+    int callbackID;
     remote_nonnull_network net;
     int event;
     int detail;
diff --git a/src/remote_protocol-structs b/src/remote_protocol-structs
index 7373d65..e58482e 100644
--- a/src/remote_protocol-structs
+++ b/src/remote_protocol-structs
@@ -2330,17 +2330,16 @@ struct remote_connect_get_cpu_model_names_ret {
 };
 struct remote_connect_network_event_register_any_args {
         int                        eventID;
+        remote_network             net;
 };
 struct remote_connect_network_event_register_any_ret {
-        int                        cb_registered;
+        int                        callbackID;
 };
 struct remote_connect_network_event_deregister_any_args {
-        int                        eventID;
-};
-struct remote_connect_network_event_deregister_any_ret {
-        int                        cb_registered;
+        int                        callbackID;
 };
 struct remote_network_event_lifecycle_msg {
+        int                        callbackID;
         remote_nonnull_network     net;
         int                        event;
         int                        detail;
-- 
1.8.4.2




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