r21230: added the hooks needed in the cluster layer and the messaging code for

handling messages to remote nodes. Implemented dummy functions in the
'local' cluster backend for the messaging hooks, and modified the
messaging layer to check if the destination is remote and redirect
messages via the cluster layer
(This used to be commit 4474552e8fb73efebef32ad8480d7fe9a1e379ef)

7 files changed, 161 insertions, 10 deletions

diff --git a/source4/cluster/cluster.c b/source4/cluster/cluster.c
index 16de01de07..ea800d2f62 100644
--- a/source4/cluster/cluster.c
+++ b/source4/cluster/cluster.c
@@ -33,11 +33,11 @@ void cluster_set_ops(struct cluster_ops *new_ops)
 }
 
 /*
-  not a nice abstraction :(
+  an ugly way of getting at the backend handle (eg. ctdb context) via the cluster API
 */
-void *cluster_private(void)
+void *cluster_backend_handle(void)
 {
-	return ops->private;
+	return ops->backend_handle(ops);
 }
 
 /* by default use the local ops */
@@ -46,8 +46,6 @@ static void cluster_init(void)
 	if (ops == NULL) cluster_local_init();
 }
 
-
-
 /*
   server a server_id for the local node
 */
@@ -76,3 +74,24 @@ struct tdb_wrap *cluster_tdb_tmp_open(TALLOC_CTX *mem_ctx, const char *dbname, i
 	cluster_init();
 	return ops->cluster_tdb_tmp_open(ops, mem_ctx, dbname, flags);
 }
+
+
+/*
+  register a callback function for a messaging endpoint
+*/
+NTSTATUS cluster_message_init(struct messaging_context *msg, struct server_id server,
+			      void (*handler)(struct messaging_context *, 
+					      struct server_id, uint32_t, DATA_BLOB))
+{
+	cluster_init();
+	return ops->message_init(ops, msg, server, handler);
+}
+
+/*
+  send a message to another node in the cluster
+*/
+NTSTATUS cluster_message_send(struct server_id server, uint32_t msg_type, DATA_BLOB *data)
+{
+	cluster_init();
+	return ops->message_send(ops, server, msg_type, data);
+}
diff --git a/source4/cluster/cluster.h b/source4/cluster/cluster.h
index f56a8e9bb6..6f076e7f78 100644
--- a/source4/cluster/cluster.h
+++ b/source4/cluster/cluster.h
@@ -28,10 +28,23 @@
 */
 #define cluster_id_equal(id1, id2) ((id1)->id == (id2)->id && (id1)->node == (id2)->node)
 
+/*
+  test for same cluster node
+*/
+#define cluster_node_equal(id1, id2) ((id1)->node == (id2)->node)
+
+struct messaging_context;
+typedef void (*cluster_message_fn_t)(struct messaging_context *, 
+				     struct server_id, uint32_t, DATA_BLOB);
+
 /* prototypes */
 struct server_id cluster_id(uint32_t id);
 const char *cluster_id_string(TALLOC_CTX *mem_ctx, struct server_id id);
 struct tdb_wrap *cluster_tdb_tmp_open(TALLOC_CTX *mem_ctx, const char *dbname, int flags);
-void *cluster_private(void);
+void *cluster_backend_handle(void);
+
+NTSTATUS cluster_message_init(struct messaging_context *msg, struct server_id server,
+			      cluster_message_fn_t handler);
+NTSTATUS cluster_message_send(struct server_id server, uint32_t msg_type, DATA_BLOB *data);
 
 #endif
diff --git a/source4/cluster/cluster_private.h b/source4/cluster/cluster_private.h
index 12d57badd0..2dc749d890 100644
--- a/source4/cluster/cluster_private.h
+++ b/source4/cluster/cluster_private.h
@@ -29,6 +29,13 @@ struct cluster_ops {
 					 TALLOC_CTX *, struct server_id );
 	struct tdb_wrap *(*cluster_tdb_tmp_open)(struct cluster_ops *,
 						 TALLOC_CTX *, const char *, int);
+	void *(*backend_handle)(struct cluster_ops *);
+	NTSTATUS (*message_init)(struct cluster_ops *ops, 
+				 struct messaging_context *msg, struct server_id server,
+				 cluster_message_fn_t handler);
+	NTSTATUS (*message_send)(struct cluster_ops *ops,
+				 struct server_id server, uint32_t msg_type, 
+				 DATA_BLOB *data);	
 	void *private; /* backend state */
 };
 
diff --git a/source4/cluster/ctdb/brlock_ctdb.c b/source4/cluster/ctdb/brlock_ctdb.c
index ffc5facbb4..04f617beb9 100644
--- a/source4/cluster/ctdb/brlock_ctdb.c
+++ b/source4/cluster/ctdb/brlock_ctdb.c
@@ -105,7 +105,8 @@ static void show_locks(const char *op, struct lock_struct *locks, int count)
 static struct brl_context *brl_ctdb_init(TALLOC_CTX *mem_ctx, struct server_id server, 
 				    struct messaging_context *messaging_ctx)
 {
-	struct ctdb_context *ctdb = talloc_get_type(cluster_private(), struct ctdb_context);
+	struct ctdb_context *ctdb = talloc_get_type(cluster_backend_handle(), 
+						    struct ctdb_context);
 	struct brl_context *brl;
 
 	brl = talloc(mem_ctx, struct brl_context);
@@ -911,7 +912,8 @@ static const struct brlock_ops brlock_tdb_ops = {
 
 void brl_ctdb_init_ops(void)
 {
-	struct ctdb_context *ctdb = talloc_get_type(cluster_private(), struct ctdb_context);
+	struct ctdb_context *ctdb = talloc_get_type(cluster_backend_handle(), 
+						    struct ctdb_context);
 
 	brl_set_ops(&brlock_tdb_ops);
 
diff --git a/source4/cluster/ctdb/ctdb_cluster.c b/source4/cluster/ctdb/ctdb_cluster.c
index 1d8d3a5252..464cb8ecba 100644
--- a/source4/cluster/ctdb/ctdb_cluster.c
+++ b/source4/cluster/ctdb/ctdb_cluster.c
@@ -39,7 +39,8 @@ struct cluster_state {
 */
 static struct server_id ctdb_id(struct cluster_ops *ops, uint32_t id)
 {
-	struct ctdb_context *ctdb = ops->private;
+	struct cluster_state *state = ops->private;
+	struct ctdb_context *ctdb = state->ctdb;
 	struct server_id server_id;
 	server_id.node = ctdb_get_vnn(ctdb);
 	server_id.id = id;
@@ -81,10 +82,43 @@ static struct tdb_wrap *ctdb_tdb_tmp_open(struct cluster_ops *ops,
 	return w;
 }
 
+/*
+  get at the ctdb handle
+*/
+static void *ctdb_backend_handle(struct cluster_ops *ops)
+{
+	struct cluster_state *state = ops->private;
+	return (void *)state->ctdb;
+}
+
+/*
+  setup a handler for ctdb messages
+*/
+static NTSTATUS ctdb_message_init(struct cluster_ops *ops,
+				  struct messaging_context *msg, 
+				  struct server_id server,
+				  cluster_message_fn_t handler)
+{
+	return NT_STATUS_OK;
+}
+
+/*
+  send a ctdb message to another node
+*/
+static NTSTATUS ctdb_message_send(struct cluster_ops *ops,
+				  struct server_id server, uint32_t msg_type, 
+				  DATA_BLOB *data)
+{
+	return NT_STATUS_INVALID_DEVICE_REQUEST;
+}
+
 static struct cluster_ops cluster_ctdb_ops = {
 	.cluster_id           = ctdb_id,
 	.cluster_id_string    = ctdb_id_string,
 	.cluster_tdb_tmp_open = ctdb_tdb_tmp_open,
+	.backend_handle       = ctdb_backend_handle,
+	.message_init         = ctdb_message_init,
+	.message_send         = ctdb_message_send,
 	.private           = NULL
 };
 
@@ -114,7 +148,7 @@ void cluster_ctdb_init(struct event_context *ev)
 	state->ctdb = ctdb_init(ev);
 	if (state->ctdb == NULL) goto failed;
 
-	cluster_ctdb_ops.private = state->ctdb;
+	cluster_ctdb_ops.private = state;
 
 	ret = ctdb_set_transport(state->ctdb, transport);
 	if (ret == -1) {
diff --git a/source4/cluster/local.c b/source4/cluster/local.c
index 28a0576acc..338bac500a 100644
--- a/source4/cluster/local.c
+++ b/source4/cluster/local.c
@@ -65,10 +65,42 @@ static struct tdb_wrap *local_tdb_tmp_open(struct cluster_ops *ops,
 	return w;
 }
 
+/*
+  dummy backend handle function
+*/
+static void *local_backend_handle(struct cluster_ops *ops)
+{
+	return NULL;
+}
+
+/*
+  dummy message init function - not needed as all messages are local
+*/
+static NTSTATUS local_message_init(struct cluster_ops *ops,
+				   struct messaging_context *msg, 
+				   struct server_id server,
+				   cluster_message_fn_t handler)
+{
+	return NT_STATUS_OK;
+}
+
+/*
+  dummy message send
+*/
+static NTSTATUS local_message_send(struct cluster_ops *ops,
+				   struct server_id server, uint32_t msg_type, 
+				   DATA_BLOB *data)
+{
+	return NT_STATUS_INVALID_DEVICE_REQUEST;
+}
+
 static struct cluster_ops cluster_local_ops = {
 	.cluster_id           = local_id,
 	.cluster_id_string    = local_id_string,
 	.cluster_tdb_tmp_open = local_tdb_tmp_open,
+	.backend_handle       = local_backend_handle,
+	.message_init         = local_message_init,
+	.message_send         = local_message_send,
 	.private              = NULL
 };
 
diff --git a/source4/lib/messaging/messaging.c b/source4/lib/messaging/messaging.c
index 691db2b961..a043937733 100644
--- a/source4/lib/messaging/messaging.c
+++ b/source4/lib/messaging/messaging.c
@@ -152,6 +152,37 @@ static void messaging_dispatch(struct messaging_context *msg, struct messaging_r
 	rec->header->length = 0;
 }
 
+/*
+  handler for messages that arrive from other nodes in the cluster
+*/
+static void cluster_message_handler(struct messaging_context *msg, struct server_id from,
+				    uint32_t msg_type, DATA_BLOB packet)
+{
+	struct messaging_rec *rec;
+
+	rec = talloc(msg, struct messaging_rec);
+	if (rec == NULL) {
+		smb_panic("Unable to allocate messaging_rec");
+	}
+
+	talloc_steal(rec, packet.data);
+	rec->msg           = msg;
+	rec->path          = msg->path;
+	rec->header        = (struct messaging_header *)packet.data;
+	rec->packet        = packet;
+
+	if (packet.length != sizeof(*rec->header) + rec->header->length) {
+		DEBUG(0,("messaging: bad message header size %d should be %d\n", 
+			 rec->header->length, (int)(packet.length - sizeof(*rec->header))));
+		talloc_free(rec);
+		return;
+	}
+
+	messaging_dispatch(msg, rec);
+	talloc_free(rec);
+}
+
+
 
 /*
   try to send the message
@@ -375,6 +406,12 @@ NTSTATUS messaging_send(struct messaging_context *msg, struct server_id server,
 	NTSTATUS status;
 	size_t dlength = data?data->length:0;
 
+	if (!cluster_node_equal(&msg->server_id, &server)) {
+		/* the destination is on another node - dispatch via
+		   the cluster layer */
+		return cluster_message_send(server, msg_type, data);
+	}
+
 	rec = talloc(msg, struct messaging_rec);
 	if (rec == NULL) {
 		return NT_STATUS_NO_MEMORY;
@@ -464,6 +501,13 @@ struct messaging_context *messaging_init(TALLOC_CTX *mem_ctx,
 		return NULL;
 	}
 
+	/* setup a handler for messages from other cluster nodes, if appropriate */
+	status = cluster_message_init(msg, server_id, cluster_message_handler);
+	if (!NT_STATUS_IS_OK(status)) {
+		talloc_free(msg);
+		return NULL;
+	}
+
 	if (ev == NULL) {
 		ev = event_context_init(msg);
 	}