avpops: add avp_shuffle function which randomly reorders AVPs

modules/avpops/avpops.c

@@ -107,6 +107,7 @@ static int fixup_free_avp_subst_p1(void** param);
 static int fixup_free_avp_subst_p2(void** param);
 static int fixup_free_pvname_list(void** param);
 static int fixup_free_avp_dbparam(void** param);
+static int fixup_avp_shuffle_name(void** param);
 
 static int w_print_avps(struct sip_msg* msg, char* foo, char *bar);
 static int w_dbload_avps(struct sip_msg* msg, void* source,
@@ -121,6 +122,7 @@ static int w_async_dbquery_avps(struct sip_msg* msg, async_ctx *ctx,
                                 str* query, void* dest, void* url);
 static int w_delete_avps(struct sip_msg* msg, void* param);
 static int w_copy_avps(struct sip_msg* msg, void* name1, void *name2);
+static int w_shuffle_avps(struct sip_msg* msg, void* param);
 static int w_pushto_avps(struct sip_msg* msg, void* destination, void *param);
 static int w_check_avps(struct sip_msg* msg, void* param, void *check);
 static int w_op_avps(struct sip_msg* msg, char* param, char *op);
@@ -183,6 +185,11 @@ static cmd_export_t cmds[] = {
 		REQUEST_ROUTE|FAILURE_ROUTE|BRANCH_ROUTE|ONREPLY_ROUTE|LOCAL_ROUTE|
 		STARTUP_ROUTE|TIMER_ROUTE|EVENT_ROUTE},
 
+	{"avp_shuffle",   (cmd_function)w_shuffle_avps,  {
+		{CMD_PARAM_STR|CMD_PARAM_NO_EXPAND, fixup_avp_shuffle_name, fixup_free_pkg}, {0, 0, 0}},
+		REQUEST_ROUTE|FAILURE_ROUTE|BRANCH_ROUTE|ONREPLY_ROUTE|LOCAL_ROUTE|
+		STARTUP_ROUTE|TIMER_ROUTE|EVENT_ROUTE},
+
 	{"avp_pushto", (cmd_function)w_pushto_avps, {
 		{CMD_PARAM_STR|CMD_PARAM_NO_EXPAND, fixup_pushto_avp_p1, fixup_free_pkg},
 		{CMD_PARAM_STR|CMD_PARAM_NO_EXPAND, fixup_pushto_avp_p2, fixup_free_pkg}, {0, 0, 0}},
@@ -843,6 +850,44 @@ static int fixup_copy_avp(void** param, int param_no)
 	return E_UNSPEC;
 }
 
+static int fixup_avp_shuffle_name(void** param)
+{
+	struct fis_param *ap=NULL;
+	char *s;
+	str cpy;
+
+	if (pkg_nt_str_dup(&cpy, (str *)*param) < 0) {
+		LM_ERR("oom\n");
+		return -1;
+	}
+	s = cpy.s;
+
+	ap = avpops_parse_pvar(s);
+	if (ap==0)
+	{
+		LM_ERR("unable to get"
+			" pseudo-variable in param \n");
+		goto err_free;
+	}
+	if (ap->u.sval.type!=PVT_AVP)
+	{
+		LM_ERR("bad param; expected : $avp(name)\n");
+		goto err_free;
+	}
+	ap->opd|=AVPOPS_VAL_PVAR;
+	ap->type = AVPOPS_VAL_PVAR;
+
+	*param=(void*)ap;
+	pkg_free(cpy.s);
+
+	return 0;
+
+err_free:
+	pkg_free(cpy.s);
+	pkg_free(ap);
+	return E_UNSPEC;
+}
+
 static int fixup_pushto_avp(void** param, int param_no)
 {
 	struct fis_param *ap = NULL;
@@ -1485,6 +1530,11 @@ static int w_copy_avps(struct sip_msg* msg, void* name1, void *name2)
 								(struct fis_param*)name2);
 }
 
+static int w_shuffle_avps(struct sip_msg* msg, void* param)
+{
+	return ops_shuffle_avp ( msg, (struct fis_param*)param);
+}
+
 static int w_pushto_avps(struct sip_msg* msg, void* destination, void *param)
 {
 	return ops_pushto_avp ( msg, (struct fis_param*)destination,

modules/avpops/avpops_impl.c

@@ -1036,6 +1036,49 @@ int ops_copy_avp( struct sip_msg* msg, struct fis_param* src,
 	return -1;
 }
 
+int ops_shuffle_avp( struct sip_msg* msg, struct fis_param* src)
+{
+	struct usr_avp *src_avp, *rnd_avp;
+	struct usr_avp *temp_avp = NULL;
+	int_str src_val, rnd_val;
+	unsigned short avp_type;
+	int avp_name;
+	int n, rnd_idx;
+
+	/* get avp src name */
+	if(avpops_get_aname(msg, src, &avp_name, &avp_type)!=0)
+	{
+		LM_ERR("failed to get src AVP name\n");
+		goto error;
+	}
+
+	/* count AVPs */
+	n = 0;
+	while ((temp_avp=search_first_avp(avp_type, avp_name, NULL, temp_avp)) != 0)
+		n++;
+
+	/* randomize AVPs */
+	for ( ; n>1; n-- ) {
+		rnd_idx = random() % n;
+		if (rnd_idx == (n-1))
+			continue;
+
+		LM_DBG("swapping [%d] <--> [%d]\n", (n-1), rnd_idx);
+
+		src_avp = search_index_avp(avp_type, avp_name, &src_val, (n-1));
+		rnd_avp = search_index_avp(avp_type, avp_name, &rnd_val, rnd_idx);
+
+		if ( replace_avp(avp_type|(rnd_avp->flags&AVP_VAL_STR), avp_name, rnd_val, (n-1))==-1 ||
+					replace_avp(avp_type|(src_avp->flags&AVP_VAL_STR), avp_name, src_val, rnd_idx)==-1 ) {
+			LM_ERR("failed to swap avp\n");
+			goto error;
+		}
+	}
+
+	return 1;
+error:
+	return -1;
+}
 
 #define STR_BUF_SIZE  1024
 static char str_buf[STR_BUF_SIZE];

modules/avpops/avpops_impl.h

@@ -150,6 +150,9 @@ int ops_delete_avp(struct sip_msg* msg,
 int ops_copy_avp(struct sip_msg* msg, struct fis_param* name1,
 								struct fis_param* name2);
 
+int ops_shuffle_avp(struct sip_msg* msg,
+								struct fis_param *param);
+
 int ops_pushto_avp(struct sip_msg* msg, struct fis_param* dst,
 								struct fis_param* ap);
 

modules/avpops/doc/avpops_admin.xml

@@ -976,6 +976,45 @@ avp_op("$avp(number)", "sub/$avp(number2)/d");
 ...
 if(is_avp_set("$avp(foo)"))
     xlog("AVP with name 'foo' is set!\n");
+...
+				</programlisting>
+			</example>
+		</section>
+		<section id="func_avp_shuffle" xreflabel="avp_shuffle()">
+			<title>
+				<function moreinfo="none">avp_shuffle(name)
+				</function>
+			</title>
+			<para>
+			Randomly shuffles AVPs with <emphasis>name</emphasis>.
+			</para>
+			<para>Meaning of the parameters is as follows:</para>
+			<itemizedlist>
+			<listitem>
+				<para><emphasis>name (string, no expand)</emphasis> - name of AVP to shuffle.
+				Parameter syntax is:
+				<itemizedlist>
+					<listitem><para><emphasis>
+					name = avp_name
+					</emphasis></para></listitem>
+				</itemizedlist>
+				</para>
+			</listitem>
+			</itemizedlist>
+			<para>
+			This function can be used from REQUEST_ROUTE, FAILURE_ROUTE,
+			BRANCH_ROUTE, LOCAL_ROUTE and ONREPLY_ROUTE.
+			</para>
+			<example>
+				<title><function>avp_shuffle</function> usage</title>
+				<programlisting format="linespecific">
+...
+$avp(foo) := "str1";
+$avp(foo)  = "str2";
+$avp(foo)  = "str3";
+xlog("Initial AVP list is: $(avp(foo)[*])\n");       # str3 str2 str1
+if(avp_shuffle("$avp(foo)"))
+    xlog("Shuffled AVP list is: $(avp(foo)[*])\n");  # str1, str3, str2 (for example)
 ...
 				</programlisting>
 			</example>