keepalive: Add ability to disable keepalive messages

The docs for virConnectSetKeepAlive() advertise that this function
should be able to disable keepalives on negative or zero interval time.

This patch removes the check that prohibited this and adds code to
disable keepalives on negative/zero interval.

* src/libvirt.c: virConnectSetKeepAlive(): - remove check for negative
                                             values
* src/rpc/virnetclient.c
* src/rpc/virnetclient.h: - add virNetClientKeepAliveStop() to disable
                            keepalive messages
* src/remote/remote_driver.c: remoteSetKeepAlive(): -add ability to
                                                     disable keepalives
(cherry picked from commit 6446a9e20c)

src/libvirt.c

@@ -18344,6 +18344,10 @@ error:
  * messages.  Failure to do so may result in connections being closed
  * unexpectedly.
  *
+ * Note: This API function controls only keepalive messages sent by the client.
+ * If the server is configured to use keepalive you still need to run the event
+ * loop to respond to them, even if you disable keepalives by this function.
+ *
  * Returns -1 on error, 0 on success, 1 when remote party doesn't support
  * keepalive messages.
  */
@@ -18363,12 +18367,6 @@ int virConnectSetKeepAlive(virConnectPtr conn,
         return -1;
     }
 
-    if (interval <= 0) {
-        virLibConnError(VIR_ERR_INVALID_ARG,
-                        _("negative or zero interval make no sense"));
-        goto error;
-    }
-
     if (conn->driver->setKeepAlive) {
         ret = conn->driver->setKeepAlive(conn, interval, count);
         if (ret < 0)

src/probes.d

@@ -78,7 +78,7 @@ provider libvirt {
 	probe rpc_keepalive_ref(void *ka, void *client, int refs);
 	probe rpc_keepalive_free(void *ka, void *client, int refs);
 	probe rpc_keepalive_start(void *ka, void *client, int interval, int count);
-	probe rpc_keepalive_stop(void *ka, void *client);
+	probe rpc_keepalive_stop(void *ka, void *client, bool all);
 	probe rpc_keepalive_send(void *ka, void *client, int prog, int vers, int proc);
 	probe rpc_keepalive_received(void *ka, void *client, int prog, int vers, int proc);
 	probe rpc_keepalive_timeout(void *ka, void *client, int coundToDeath, int idle);

src/remote/remote_driver.c

@@ -4647,7 +4647,12 @@ remoteSetKeepAlive(virConnectPtr conn, int interval, unsigned int count)
         goto cleanup;
     }
 
-    ret = virNetClientKeepAliveStart(priv->client, interval, count);
+    if (interval > 0) {
+        ret = virNetClientKeepAliveStart(priv->client, interval, count);
+    } else {
+        virNetClientKeepAliveStop(priv->client);
+        ret = 0;
+    }
 
 cleanup:
     remoteDriverUnlock(priv);

src/rpc/virkeepalive.c

@@ -372,32 +372,48 @@ cleanup:
 }
 
 
-void
-virKeepAliveStop(virKeepAlivePtr ka)
+static void
+virKeepAliveStopInternal(virKeepAlivePtr ka, bool all)
 {
     virKeepAliveLock(ka);
 
     PROBE(RPC_KEEPALIVE_STOP,
-          "ka=%p client=%p",
-          ka, ka->client);
+          "ka=%p client=%p all=%d",
+          ka, ka->client, all);
 
     if (ka->timer > 0) {
         virEventRemoveTimeout(ka->timer);
         ka->timer = -1;
     }
 
-    if (ka->responseTimer > 0) {
-        virEventRemoveTimeout(ka->responseTimer);
-        ka->responseTimer = -1;
+    if (all) {
+        if (ka->responseTimer > 0) {
+            virEventRemoveTimeout(ka->responseTimer);
+            ka->responseTimer = -1;
+        }
+
+        virNetMessageFree(ka->response);
+        ka->response = NULL;
     }
 
-    virNetMessageFree(ka->response);
-    ka->response = NULL;
-
     virKeepAliveUnlock(ka);
 }
 
 
+void
+virKeepAliveStop(virKeepAlivePtr ka)
+{
+    virKeepAliveStopInternal(ka, true);
+}
+
+
+void
+virKeepAliveStopSending(virKeepAlivePtr ka)
+{
+    virKeepAliveStopInternal(ka, false);
+}
+
+
 bool
 virKeepAliveCheckMessage(virKeepAlivePtr ka,
                          virNetMessagePtr msg)

src/rpc/virkeepalive.h

@@ -49,6 +49,7 @@ int virKeepAliveStart(virKeepAlivePtr ka,
                       int interval,
                       unsigned int count);
 void virKeepAliveStop(virKeepAlivePtr ka);
+void virKeepAliveStopSending(virKeepAlivePtr ka);
 
 bool virKeepAliveCheckMessage(virKeepAlivePtr ka,
                               virNetMessagePtr msg);

src/rpc/virnetclient.c

@@ -248,6 +248,14 @@ virNetClientKeepAliveStart(virNetClientPtr client,
     return ret;
 }
 
+void
+virNetClientKeepAliveStop(virNetClientPtr client)
+{
+    virNetClientLock(client);
+    virKeepAliveStopSending(client->keepalive);
+    virNetClientUnlock(client);
+}
+
 static void
 virNetClientKeepAliveDeadCB(void *opaque)
 {

src/rpc/virnetclient.h

@@ -104,4 +104,6 @@ int virNetClientKeepAliveStart(virNetClientPtr client,
                                int interval,
                                unsigned int count);
 
+void virNetClientKeepAliveStop(virNetClientPtr client);
+
 #endif /* __VIR_NET_CLIENT_H__ */