Added support for yang presence and no-presence containers.

CHANGELOG.md

@@ -1,29 +1,23 @@
 # Clixon CHANGELOG
 
-- Extended ietf-ip example with ietf-routing.
+Major changes:
+- Added support for yang presence and no-presence containers. Previous default was "presence".
 
-- Added YANG RPC support, with example rpc documentation and testcase (test7.sh).
+- Added YANG RPC support for nentconf and CLI. With example rpc documentation and testcase. This replaces the previous "downcall" mechanism.
 
-- Added completion for generated cli leafrefs for both absolute and relatve paths.
+- Enhanced leafref functionality: (1) validation for leafref forward and backward references; (2)CLI completion for generated cli leafrefs for both absolute and relatve paths.
 	
-- Added validation for leafref forward and backward references.
+- Added state data: Netconf <get> operation, new backend plugin callback: "plugin_statedata()" for retreiving state data.
-	
-- Added new backend plugin callback: "plugin_statedata()" for retreiving state data
 
+Minor changes:
+- Removed 'margin' parameter of yang_print().
+- Extended example with ietf-routing (not only ietf-ip) for rpc operations.
 - Added yang dir with ietf-netconf and clixon-config yang specs for internal usage.
-
-- Added state data: Netconf <get> operation introduced; Error when
-  adding state data in <edit-config>.
-
 - Fixed bug where cli set of leaf-list were doubled, eg cli set foo -> foofoo
-
 - Restricted yang (sub)module file match to match RFC6020 exactly
-
-- Generalized yang type resolution to all included (sub)modules not just the topmost
-
 - Generic map_str2int generic mapping tables
-
 - Removed vector return values from xmldb_get()
+- Generalized yang type resolution to all included (sub)modules not just the topmost
 	
 ## 3.3.1 June 7 2017
 

apps/backend/backend_client.c

@@ -242,14 +242,9 @@ from_client_get_config(clicon_handle h,
 	goto ok;
     }
     cprintf(cbret, "<rpc-reply><data>");
-    if (xret!=NULL){
+    if (xret!=NULL && 
-	if (xml_child_nr(xret)){
+	clicon_xml2cbuf(cbret, xret, 0, 0) < 0)
-	    if (xml_name_set(xret, "config") < 0)
+	    goto done;
-		goto done;
-	    if (clicon_xml2cbuf(cbret, xret, 0, 0) < 0)
-		goto done;
-	}
-    }
     cprintf(cbret, "</data></rpc-reply>");
  ok:
     retval = 0;

apps/cli/cli_show.c

@@ -387,7 +387,7 @@ show_yang(clicon_handle h,
   }
   else
     yn = (yang_node*)yspec;
-  yang_print(stdout, yn, 0);
+  yang_print(stdout, yn);
   return 0;
 }
 int show_yangv(clicon_handle h, cvec *vars, cvec *argv)

apps/netconf/netconf_plugin.c

@@ -238,6 +238,8 @@ netconf_plugin_callbacks(clicon_handle h,
     yang_spec     *yspec;
     yang_stmt     *yrpc;
     yang_stmt     *yinput;
+    yang_stmt     *youtput;
+    cxobj         *xoutput;
     find_rpc_arg   fra = {0,0};
     int            ret;
 
@@ -279,6 +281,18 @@ netconf_plugin_callbacks(clicon_handle h,
 	 */
 	if (clicon_rpc_netconf_xml(h, xml_parent(xn), xret, NULL) < 0)
 	    goto done;
+	/* Sanity check of outgoing XML */
+	if ((youtput = yang_find((yang_node*)yrpc, Y_OUTPUT, NULL)) != NULL){
+	    xoutput=xpath_first(*xret, "/");
+	    xml_spec_set(xoutput, youtput); /* needed for xml_spec_populate */
+	    if (xml_apply(xoutput, CX_ELMNT, xml_spec_populate, yinput) < 0)
+		goto done;
+	    if (xml_apply(xoutput, CX_ELMNT, 
+			  (xml_applyfn_t*)xml_yang_validate_all, NULL) < 0)
+		goto done;
+	    if (xml_yang_validate_add(xoutput, NULL) < 0)
+		goto done;
+	}
 	retval = 1; /* handled by callback */
 	goto done;
     }

datastore/keyvalue/clixon_keyvalue.c

@@ -673,7 +673,7 @@ put(char               *dbfile,
     clicon_debug(1, "%s xk0:%s ys:%s", __FUNCTION__, xk0, ys->ys_argument);
     if (debug){
 	xml_print(stderr, xt);
-	//	yang_print(stderr, (yang_node*)ys, 0);
+	//	yang_print(stderr, (yang_node*)ys);
     }
     if ((opstr = xml_find_value(xt, "operation")) != NULL)
 	if (xml_operation(opstr, &op) < 0)

datastore/text/clixon_xmldb_text.c

@@ -665,6 +665,50 @@ text_modify_top(cxobj              *x0,
     return retval;
 }
 
+/*! For containers without presence and no children, remove
+ * @param[in]   x       XML tree node
+ * @note This should really be unnecessary since yspec should be set on creation
+ * @code
+ * xml_apply(xc, CX_ELMNT, xml_spec_populate, yspec)
+ * @endcode
+ * See section 7.5.1 in rfc6020bis-02.txt:
+ * No presence:
+ * those that exist only for organizing the hierarchy of data nodes:
+ * the container has no meaning of its own, existing
+ * only to contain child nodes.  This is the default style.
+ * (Remove these if no children)
+ * Presence:
+ * the presence of the container itself is
+ * configuration data, representing a single bit of configuration data.
+ * The container acts as both a configuration knob and a means of
+ * organizing related configuration.  These containers are explicitly
+ * created and deleted.
+ * (Dont touch these)
+ */
+int
+xml_container_presence(cxobj  *x, 
+		       void   *arg)
+{
+    int        retval = -1;
+    char      *name;
+    yang_stmt *y;  /* yang node */
+
+    name = xml_name(x);
+    if ((y = (yang_stmt*)xml_spec(x)) == NULL){
+	clicon_log(LOG_WARNING, "%s: no xml_spec(%s)", __FUNCTION__, name);
+	retval = 0;
+	goto done;
+    }
+    /* Mark node that is: container, have no children, dont have presence */
+    if (y->ys_keyword == Y_CONTAINER && 
+	xml_child_nr(x)==0 &&
+	yang_find((yang_node*)y, Y_PRESENCE, NULL) == NULL)
+	xml_flag_set(x, XML_FLAG_MARK); /* Mark, remove later */
+    retval = 0;
+ done:
+    return retval;
+}
+
 /*! Modify database provided an xml tree and an operation
  * This is a clixon datastore plugin of the the xmldb api
  * @see xmldb_put
@@ -745,6 +789,12 @@ text_put(xmldb_handle        xh,
     if (xml_apply(x0, CX_ELMNT, (xml_applyfn_t*)xml_flag_reset, 
 		  (void*)XML_FLAG_NONE) < 0)
 	goto done;
+    /* Mark non-presence containers that do not have children */
+    if (xml_apply(x0, CX_ELMNT, (xml_applyfn_t*)xml_container_presence, NULL) < 0)
+	goto done;
+    /* Remove (prune) nodes that are marked (non-presence containers w/o children) */
+    if (xml_tree_prune_flagged(x0, XML_FLAG_MARK, 1) < 0)
+	goto done;
     // output:
     /* Print out top-level xml tree after modification to file */
     if ((cb = cbuf_new()) == NULL){

doc/FAQ.md

@@ -197,8 +197,10 @@ They are documented in [CLIgen tutorial](https://github.com/olofhagsand/cligen/b
 ## How do I write a validation function?
 Similar to a commit function, but instead write the transaction_validate() function.
 Check for inconsistencies in the XML trees and if they fail, make an clicon_err() call.
+```
     clicon_err(OE_PLUGIN, 0, "Route %s lacks ipv4 addr", name);
     return -1;
+```
 The validation or commit will then be aborted.
 
 ## How do I write a state data callback function?
@@ -210,3 +212,45 @@ To return state data, you need to write a backend state data callback
 with the name "plugin_statedata()" where you return an XML tree.
 
 Please look at the example for an example on how to write a state data callback.
+
+## How do I write an RPC function?
+
+A YANG RPC is an application specific operation. Example:
+```
+   rpc fib-route {
+      input {
+         leaf inarg { type string; }
+      }
+      output {
+         leaf outarg { type string; }
+      }
+   }
+```
+which defines the fib-route operation present in the example (the arguments have been changed).
+
+Clixon automatically relays the RPC to the clixon backend. To
+implement the RFC, you need to register an RPC callback in the backend plugin:
+Example:
+```
+int
+plugin_init(clicon_handle h)
+{
+...
+   backend_rpc_cb_register(h, fib_route, NULL, "fib-route");
+...
+}
+```
+And then define the callback itself:
+```
+static int 
+fib_route(clicon_handle h,            /* Clicon handle */
+	  cxobj        *xe,           /* Request: <rpc><xn></rpc> */
+	  struct client_entry *ce,    /* Client session */
+	  cbuf         *cbret,        /* Reply eg <rpc-reply>... */
+	  void         *arg)          /* Argument given at register */
+{
+    cprintf(cbret, "<rpc-reply><ok/></rpc-reply>");    
+    return 0;
+}
+```
+Here, the callback is over-simplified.

example/README.md

@@ -103,6 +103,13 @@ fib_route(clicon_handle h,
     cprintf(cbret, "<rpc-reply><ok/></rpc-reply>");    
     return 0;
 }
+int
+plugin_init(clicon_handle h)
+{
+...
+   backend_rpc_cb_register(h, fib_route, NULL, "fib-route");
+...
+}
 ```
 ## State data
 

example/routing_backend.c

@@ -121,13 +121,16 @@ notification_timer_setup(clicon_handle h)
 
 /*! IETF Routing fib-route rpc */
 static int 
-fib_route(clicon_handle h, 
+fib_route(clicon_handle h,            /* Clicon handle */
 	  cxobj        *xe,           /* Request: <rpc><xn></rpc> */
 	  struct client_entry *ce,    /* Client session */
 	  cbuf         *cbret,        /* Reply eg <rpc-reply>... */
 	  void         *arg)          /* Argument given at register */
 {
-    cprintf(cbret, "<rpc-reply><ok/></rpc-reply>");    
+    cprintf(cbret, "<rpc-reply><route>"
+	    "<address-family>ipv4</address-family>"
+	    "<next-hop><next-hop-list>2.3.4.5</next-hop-list></next-hop>"
+	    "</route></rpc-reply>");    
     return 0;
 }
 

lib/clixon/clixon_yang.h

@@ -204,8 +204,8 @@ yang_stmt *yang_find(yang_node *yn, int keyword, char *argument);
 yang_stmt *yang_find_syntax(yang_node *yn, char *argument);
 yang_stmt *yang_find_topnode(yang_spec *ysp, char *name);
 
+int        yang_print(FILE *f, yang_node *yn);
 int        yang_print_cbuf(cbuf *cb, yang_node *yn, int marginal);
-int        yang_print(FILE *f, yang_node *yn, int marginal);
 int        yang_parse(clicon_handle h, const char *yang_dir, 
 		      const char *module, const char *revision, yang_spec *ysp);
 int        yang_apply(yang_node *yn, enum rfc_6020 key, yang_applyfn_t fn, 

lib/src/clixon_yang.c

@@ -682,43 +682,41 @@ quotedstring(char *s)
 }
 
 /*! Print yang specification to file
+ * @param[in]  f         File to print to.
+ * @param[in]  yn        Yang node to print
  * @see yang_print_cbuf
  */
 int
 yang_print(FILE      *f, 
-	   yang_node *yn, 
+	   yang_node *yn)
-	   int        marginal)
 {
-    yang_stmt *ys = NULL;
+    int        retval = -1;
+    cbuf      *cb = NULL;
 
-    while ((ys = yn_each(yn, ys)) != NULL) {
+    if ((cb = cbuf_new()) == NULL){
-	fprintf(f, "%*s%s", marginal, "", yang_key2str(ys->ys_keyword));
+	clicon_err(OE_YANG, errno, "%s: cbuf_new", __FUNCTION__);
-	fflush(f);
+	goto done;
-	if (ys->ys_argument){
-	    if (quotedstring(ys->ys_argument))
-		fprintf(f, " \"%s\"", ys->ys_argument);
-	    else
-		fprintf(f, " %s", ys->ys_argument);
-	}
-	if (ys->ys_len){
-	    fprintf(f, " {\n");
-	    yang_print(f, (yang_node*)ys, marginal+3);
-	    fprintf(f, "%*s%s\n", marginal, "", "}");
-	}
-	else
-	    fprintf(f, ";\n");
     }
-    return 0;
+    if (yang_print_cbuf(cb, yn, 0) < 0)
+	goto done;
+    fprintf(f, "%s", cbuf_get(cb));
+    if (cb)
+	cbuf_free(cb);
+    retval = 0;
+ done:
+    return retval;
 }
 
 /*! Print yang specification to cligen buf
+ * @param[in]  cb        Cligen buffer. This is where the pretty print is.
+ * @param[in]  yn        Yang node to print
+ * @param[in]  marginal  Tab indentation, mainly for recursion.
  * @code
  *  cbuf *cb = cbuf_new();
  *  yang_print_cbuf(cb, yn, 0);
  *  // output is in cbuf_buf(cb);
  *  cbuf_free(cb);
  * @endcode
- * @see yang_print
  */
 int
 yang_print_cbuf(cbuf      *cb,
@@ -1944,7 +1942,7 @@ yang_spec_main(clicon_handle h,
 	goto done;
     clicon_dbspec_yang_set(h, yspec);	
     if (printspec)
-	yang_print(f, (yang_node*)yspec, 0);
+	yang_print(f, (yang_node*)yspec);
     retval = 0;
   done:
     return retval;

test/README.md

@@ -4,8 +4,10 @@ This directory contains testing code for clixon and the example
 routing application:
 - clixon    A top-level script clones clixon in /tmp and starts all.sh. You can copy this file (review it first) and place as cron script
 - all.sh    Run through all tests named 'test*.sh' in this directory. Therefore, if you place a test in this directory matching 'test*.sh' it will be run automatically. 
-- test1.sh  CLI tests
+- test_cli.sh       CLI tests
-- test2.sh  Netconf tests
+- test_netconf.sh   Netconf tests
-- test3.sh  Restconf tests
+- test_restconf.sh  Restconf tests
-- test4.sh  Yang tests
+- test_yang.sh      Yang tests for constructs not in the example.
-- test5.sh  Datastore tests
+- test_leafref.sh   Yang leafref tests
+- test_datastore.sh Datastore tests
+

test/test6.sh

@@ -1,38 +0,0 @@
-#!/bin/bash
-# Test6: Yang specifics: rpc and state info
-
-# include err() and new() functions
-. ./lib.sh
-
-# For memcheck
-# clixon_netconf="valgrind --leak-check=full --show-leak-kinds=all clixon_netconf"
-clixon_netconf=clixon_netconf
-clixon_cli=clixon_cli
-
-# kill old backend (if any)
-new "kill old backend"
-sudo clixon_backend -zf $clixon_cf
-if [ $? -ne 0 ]; then
-    err
-fi
-
-new "start backend"
-# start new backend
-sudo clixon_backend -If $clixon_cf
-if [ $? -ne 0 ]; then
-    err
-fi
-new "netconf rpc"
-expecteof "$clixon_netconf -qf $clixon_cf" "<rpc><fib-route><routing-instance-name>ipv4</routing-instance-name></fib-route></rpc>]]>]]>" "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
-
-new "Kill backend"
-# Check if still alive
-pid=`pgrep clixon_backend`
-if [ -z "$pid" ]; then
-    err "backend already dead"
-fi
-# kill backend
-sudo clixon_backend -zf $clixon_cf
-if [ $? -ne 0 ]; then
-    err "kill backend"
-fi

test/test_cli.sh

@@ -31,8 +31,8 @@ new "cli tests"
 new "cli configure top"
 expectfn "$clixon_cli -1f $clixon_cf set interfaces" ""
 
-new "cli show configuration top"
+new "cli show configuration top (no presence)"
-expectfn "$clixon_cli -1f $clixon_cf show conf cli" "^interfaces$"
+expectfn "$clixon_cli -1f $clixon_cf show conf cli" ""
 
 new "cli configure delete top"
 expectfn "$clixon_cli -1f $clixon_cf delete interfaces" ""

test/test_netconf.sh

@@ -24,13 +24,13 @@ fi
 new "netconf tests"
 
 new "netconf get empty config"
-expecteof "$clixon_netconf -qf $clixon_cf" '<rpc message-id="101"><get-config><source><candidate/></source></get-config></rpc>]]>]]>' '^<rpc-reply message-id="101"><data/></rpc-reply>]]>]]>$'
+expecteof "$clixon_netconf -qf $clixon_cf" '<rpc message-id="101"><get-config><source><candidate/></source></get-config></rpc>]]>]]>' '^<rpc-reply message-id="101"><data><config/></data></rpc-reply>]]>]]>$'
 
 new "Add subtree eth/0/0 using none which should not change anything"
 expecteof "$clixon_netconf -qf $clixon_cf" "<rpc><edit-config><default-operation>none</default-operation><target><candidate/></target><config><interfaces><interface><name>eth/0/0</name></interface></interfaces></config></edit-config></rpc>]]>]]>" "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
 
 new "Check nothing added"
-expecteof "$clixon_netconf -qf $clixon_cf" '<rpc message-id="101"><get-config><source><candidate/></source></get-config></rpc>]]>]]>' '^<rpc-reply message-id="101"><data/></rpc-reply>]]>]]>$'
+expecteof "$clixon_netconf -qf $clixon_cf" '<rpc message-id="101"><get-config><source><candidate/></source></get-config></rpc>]]>]]>' '^<rpc-reply message-id="101"><data><config/></data></rpc-reply>]]>]]>$'
 
 new "Add subtree eth/0/0 using none and create which should add eth/0/0"
 expecteof "$clixon_netconf -qf $clixon_cf" '<rpc><edit-config><target><candidate/></target><config><interfaces><interface operation="create"><name>eth/0/0</name><type>eth</type></interface></interfaces></config><default-operation>none</default-operation> </edit-config></rpc>]]>]]>' "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
@@ -44,8 +44,8 @@ expecteof "$clixon_netconf -qf $clixon_cf" '<rpc><edit-config><target><candidate
 new "Delete eth/0/0 using none config"
 expecteof "$clixon_netconf -qf $clixon_cf" '<rpc><edit-config><target><candidate/></target><config><interfaces><interface operation="delete"><name>eth/0/0</name><type>eth</type></interface></interfaces></config><default-operation>none</default-operation> </edit-config></rpc>]]>]]>'  "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
 
-#new "Check deleted eth/0/0"
+new "Check deleted eth/0/0 (non-presence container)"
-#expecteof "$clixon_netconf -qf $clixon_cf" '<rpc message-id="101"><get-config><source><candidate/></source></get-config></rpc>]]>]]>' '^<rpc-reply message-id="101"><data><config><interfaces/></config></data></rpc-reply>]]>]]>$'
+expecteof "$clixon_netconf -qf $clixon_cf" '<rpc message-id="101"><get-config><source><candidate/></source></get-config></rpc>]]>]]>' '^<rpc-reply message-id="101"><data><config/></data></rpc-reply>]]>]]>$'
 
 new "Re-Delete eth/0/0 using none should generate error"
 expecteof "$clixon_netconf -qf $clixon_cf" '<rpc><edit-config><target><candidate/></target><config><interfaces><interface operation="delete"><name>eth/0/0</name><type>eth</type></interface></interfaces></config><default-operation>none</default-operation> </edit-config></rpc>]]>]]>'  "^<rpc-reply><rpc-error>"
@@ -66,7 +66,7 @@ new "netconf discard-changes"
 expecteof "$clixon_netconf -qf $clixon_cf" "<rpc><discard-changes/></rpc>]]>]]>" "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
 
 new "netconf get empty config2"
-expecteof "$clixon_netconf -qf $clixon_cf" "<rpc><get-config><source><candidate/></source></get-config></rpc>]]>]]>" "^<rpc-reply><data/></rpc-reply>]]>]]>$"
+expecteof "$clixon_netconf -qf $clixon_cf" "<rpc><get-config><source><candidate/></source></get-config></rpc>]]>]]>" "^<rpc-reply><data><config/></data></rpc-reply>]]>]]>$"
 
 new "netconf edit config eth1"
 expecteof "$clixon_netconf -qf $clixon_cf" "<rpc><edit-config><target><candidate/></target><config><interfaces><interface><name>eth1</name><type>eth</type></interface></interfaces></config></edit-config></rpc>]]>]]>" "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
@@ -117,7 +117,10 @@ new "netconf delete startup"
 expecteof "$clixon_netconf -qf $clixon_cf" "<rpc><delete-config><target><startup/></target></delete-config></rpc>]]>]]>" "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
 
 new "netconf check empty startup"
-expecteof "$clixon_netconf -qf $clixon_cf" "<rpc><get-config><source><startup/></source></get-config></rpc>]]>]]>" "^<rpc-reply><data/></rpc-reply>]]>]]>$"
+expecteof "$clixon_netconf -qf $clixon_cf" "<rpc><get-config><source><startup/></source></get-config></rpc>]]>]]>" "^<rpc-reply><data><config/></data></rpc-reply>]]>]]>$"
+
+new "netconf rpc"
+expecteof "$clixon_netconf -qf $clixon_cf" "<rpc><fib-route><routing-instance-name>ipv4</routing-instance-name><destination-address><address-family>ipv4</address-family></destination-address></fib-route></rpc>]]>]]>" "^<rpc-reply><route><address-family>ipv4</address-family><next-hop><next-hop-list>"
 
 new "netconf subscription"
 expectwait "$clixon_netconf -qf $clixon_cf" "<rpc><create-subscription><stream>ROUTING</stream></create-subscription></rpc>]]>]]>" "^<rpc-reply><ok/></rpc-reply>]]>]]><notification><event>Routing notification</event></notification>]]>]]>$" 30

test/test_yang.sh

@@ -35,7 +35,15 @@ module example{
     leaf g {
       type string;  
     }
-    container h {
+    container nopresence {
+      description "No presence should be removed if no children";
+      leaf j {
+        type string;
+      }
+    }
+    container presence {
+      description "Presence should not be removed even if no children";
+      presence "even if empty should remain";
       leaf j {
         type string;
       }
@@ -81,7 +89,7 @@ expecteof "$clixon_netconf -qf $clixon_cf -y /tmp/test" "<rpc><get-config><sourc
 new "netconf get leaf-list path"
 expecteof "$clixon_netconf -qf $clixon_cf -y /tmp/test" "<rpc><get-config><source><candidate/></source><filter type=\"xpath\" select=\"/x/f[e=hej]\"/></get-config></rpc>]]>]]>" "^<rpc-reply><data><config><x><f><e>hej</e><e>hopp</e></f></x></config></data></rpc-reply>]]>]]>$"
 
-new "netconf get (state data XXX should be some)"
+new "netconf get (should be some)"
 expecteof "$clixon_netconf -qf $clixon_cf -y /tmp/test" "<rpc><get><filter type=\"xpath\" select=\"/\"/></get></rpc>]]>]]>" "^<rpc-reply><data><config><x><y><a>1</a><b>2</b><c>5</c></y><d/></x></config></data></rpc-reply>]]>]]>$"
 
 new "cli set leaf-list"
@@ -89,10 +97,14 @@ expectfn "$clixon_cli -1f $clixon_cf -y /tmp/test set x f e foo" ""
 
 new "cli show leaf-list"
 expectfn "$clixon_cli -1f $clixon_cf -y /tmp/test show xpath /x/f/e" "<e>foo</e>"
-
 new "netconf set state data (not allowed)"
 expecteof "$clixon_netconf -qf $clixon_cf -y /tmp/test" "<rpc><edit-config><target><candidate/></target><config><state><op>42</op></state></config></edit-config></rpc>]]>]]>" "^<rpc-reply><rpc-error><error-tag>invalid-value"
 
+new "netconf set presence and not present"
+expecteof "$clixon_netconf -qf $clixon_cf -y /tmp/test" "<rpc><edit-config><target><candidate/></target><config><x><nopresence/><presence/></x></config></edit-config></rpc>]]>]]>" "^<rpc-reply><ok/></rpc-reply>]]>]]>$"
+
+new "netconf get"
+expecteof "$clixon_netconf -qf $clixon_cf -y /tmp/test" "<rpc><get-config><source><candidate/></source><filter type=\"xpath\" select=\"/x/*presence\"/></get-config></rpc>]]>]]>" "^<rpc-reply><data><config><x><presence/></x></config></data></rpc-reply>]]>]]>$"
 
 new "Kill backend"
 # Check if still alive