s4-rpc: added a module for forwarding RPC requests

dcesrv_irpc_forward_rpc_call() can be used to forward an arbitrary RPC
request to another task in Samba4, with the return being handled
asynchronously.

This is useful for forwarding DRS requests to the repl or kcc tasks

3 files changed, 116 insertions, 9 deletions

diff --git a/source4/rpc_server/common/common.h b/source4/rpc_server/common/common.h
index aacd460388..5a1d7abab9 100644
--- a/source4/rpc_server/common/common.h
+++ b/source4/rpc_server/common/common.h
@@ -25,14 +25,6 @@
 
 struct share_config;
 struct dcesrv_context;
-enum srvsvc_ShareType dcesrv_common_get_share_type(TALLOC_CTX *mem_ctx, struct dcesrv_context *dce_ctx, struct share_config *scfg);
-enum srvsvc_PlatformId dcesrv_common_get_platform_id(TALLOC_CTX *mem_ctx, struct dcesrv_context *dce_ctx);
-const char *dcesrv_common_get_lan_root(TALLOC_CTX *mem_ctx, struct dcesrv_context *dce_ctx);
-const char *dcesrv_common_get_server_name(TALLOC_CTX *mem_ctx, struct dcesrv_context *dce_ctx, const char *server_unc);
-uint32_t dcesrv_common_get_share_permissions(TALLOC_CTX *mem_ctx, struct dcesrv_context *dce_ctx, struct share_config *scfg);
-uint32_t dcesrv_common_get_share_current_users(TALLOC_CTX *mem_ctx, struct dcesrv_context *dce_ctx, struct share_config *scfg);
-const char *dcesrv_common_get_share_path(TALLOC_CTX *mem_ctx, struct dcesrv_context *dce_ctx, struct share_config *scfg);
-
 struct dcesrv_context;
 
 struct dcerpc_server_info { 
@@ -42,4 +34,6 @@ struct dcerpc_server_info {
 	uint32_t version_build;
 };
 
+#include "rpc_server/common/proto.h"
+
 #endif /* _DCERPC_SERVER_COMMON_H_ */
diff --git a/source4/rpc_server/common/forward.c b/source4/rpc_server/common/forward.c
new file mode 100644
index 0000000000..e0fac0ea08
--- /dev/null
+++ b/source4/rpc_server/common/forward.c
@@ -0,0 +1,112 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   forwarding of RPC calls to other tasks
+
+   Copyright (C) Andrew Tridgell 2009
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "librpc/gen_ndr/ndr_srvsvc.h"
+#include "librpc/gen_ndr/svcctl.h"
+#include "rpc_server/dcerpc_server.h"
+#include "rpc_server/common/common.h"
+#include "rpc_server/common/proto.h"
+#include "messaging/irpc.h"
+
+struct dcesrv_forward_state {
+	const char *opname;
+	struct dcesrv_call_state *dce_call;
+};
+
+/*
+  called when the forwarded rpc request is finished
+ */
+static void dcesrv_irpc_forward_callback(struct irpc_request *ireq)
+{
+	struct dcesrv_forward_state *st = talloc_get_type(ireq->async.private_data, 
+							  struct dcesrv_forward_state);
+	const char *opname = st->opname;
+	NTSTATUS status;
+	if (!NT_STATUS_IS_OK(ireq->status)) {
+		DEBUG(0,("IRPC callback failed for %s - %s\n",
+			 opname, nt_errstr(ireq->status)));
+		st->dce_call->fault_code = DCERPC_FAULT_CANT_PERFORM;
+	}
+	talloc_free(ireq);
+	status = dcesrv_reply(st->dce_call);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0,("%s_handler: dcesrv_reply() failed - %s\n",
+			 opname, nt_errstr(status)));
+	}
+}
+
+
+
+/*
+  forward a RPC call using IRPC to another task
+ */
+void dcesrv_irpc_forward_rpc_call(struct dcesrv_call_state *dce_call, TALLOC_CTX *mem_ctx,
+				  void *r, uint32_t callid,
+				  const struct ndr_interface_table *ndr_table,
+				  const char *dest_task, const char *opname)
+{
+	struct server_id *sid;
+	struct irpc_request *ireq;
+	struct dcesrv_forward_state *st;
+
+	st = talloc(mem_ctx, struct dcesrv_forward_state);
+	if (st == NULL) {
+		dce_call->fault_code = DCERPC_FAULT_CANT_PERFORM;
+		return;
+	}
+
+	st->dce_call = dce_call;
+	st->opname   = opname;
+
+	/* if the caller has said they can't support async calls
+	   then fail the call */
+	if (!(dce_call->state_flags & DCESRV_CALL_STATE_FLAG_MAY_ASYNC)) {
+		/* we're not allowed to reply async */
+		DEBUG(0,("%s: Not available synchronously\n", dest_task));
+		dce_call->fault_code = DCERPC_FAULT_CANT_PERFORM;
+		return;
+	}
+
+	/* find the server task */
+	sid = irpc_servers_byname(dce_call->msg_ctx, mem_ctx, dest_task);
+	if (sid == NULL || sid[0].id == 0) {
+		DEBUG(0,("%s: Unable to find %s task\n", dest_task, opname));
+		dce_call->fault_code = DCERPC_FAULT_CANT_PERFORM;
+		return;
+	}
+
+	/* forward the call */
+	ireq = irpc_call_send(dce_call->msg_ctx, sid[0], ndr_table, callid, r, mem_ctx);
+	if (ireq == NULL) {
+		DEBUG(0,("%s: Failed to forward request to %s task\n", 
+			 opname, dest_task));
+		dce_call->fault_code = DCERPC_FAULT_CANT_PERFORM;
+		return;
+	}
+
+	/* mark the request as replied async */
+	dce_call->state_flags |= DCESRV_CALL_STATE_FLAG_ASYNC;
+
+	/* setup the callback */
+	ireq->async.fn = dcesrv_irpc_forward_callback;
+	ireq->async.private_data = st;
+}
diff --git a/source4/rpc_server/config.mk b/source4/rpc_server/config.mk
index f60f83327b..93617c2c98 100644
--- a/source4/rpc_server/config.mk
+++ b/source4/rpc_server/config.mk
@@ -8,7 +8,8 @@ PRIVATE_DEPENDENCIES = LIBLDB
 # End SUBSYSTEM DCERPC_COMMON
 ################################################
 
-DCERPC_COMMON_OBJ_FILES = $(addprefix $(rpc_serversrcdir)/common/, server_info.o share_info.o)
+DCERPC_COMMON_OBJ_FILES = $(addprefix $(rpc_serversrcdir)/common/, \
+	server_info.o share_info.o forward.o)
 
 $(eval $(call proto_header_template,$(rpc_serversrcdir)/common/proto.h,$(DCERPC_COMMON_OBJ_FILES:.o=.c)))