modules/ims_registrar_scscf: new mod_param subscription_expires_range

If set this parameter randomises the subscription expiry
Works exactly the same as usrloc expires_range param

modules/ims_registrar_scscf/doc/ims_registrar_scscf_admin.xml

@@ -67,7 +67,7 @@
       contact parameters, this value will be used for newly created S-CSCF
       usrloc records. The parameter contains number of second to expire (for
       example use 3600 for one hour). If it is set to a lower value than the
-      “min_expires” parameter then it will be ignored. This
+      min_expires parameter then it will be ignored. This
       parameter can be modified via ser config framework. A random value in a
       specific interval can be selected by using the default_expires_range
       parameter</para>
@@ -87,10 +87,10 @@
       <title>default_expires_range (int)</title>
 
       <para>This parameter specifies that the expiry used for newly created
-      S-CSCF usrloc records are not fixed(when &ldquo;default_expires&rdquor;
-      applies), but a random value in the interval
-      &ldquo;[default_expires-default_expires_range%,
-      default_expires+default_expires_range%]&rdquor;. The value is between 0
+      S-CSCF usrloc records are not fixed(when default_expires
+      applies), but a random value in the intervalrdq
+      [default_expires-default_expires_range%,
+      default_expires+default_expires_range%]. The value is between 0
       and 100 and represent the maximim percentage from default_expires that
       will be substracted or added when computing the value. Default in 0,
       meaning default_expires is left unmodified. This parameter can be
@@ -144,6 +144,87 @@
 ...</programlisting>
       </example>
     </section>
+    
+    <section>
+      <title>subscription_default_expires (int)</title>
+
+      <para>If the processed message contains neither Expires HFs nor expires
+      contact parameters, this value will be used for newly created subscriptions.
+      The parameter contains number of second to expire (for example use 3600 for one hour). 
+      If it is set to a lower value than the subscription_min_expires parameter 
+      then it will be ignored. A random value in a specific interval can be selected 
+      by using the subscription_expires_range parameter</para>
+
+      <para><emphasis> Default value is 3600. </emphasis></para>
+
+      <example>
+        <title>Set <varname>subscription_default_expires</varname> parameter</title>
+
+        <programlisting format="linespecific">...
+        modparam("ims_registrar_scscf", "subscription_default_expires", 3600)
+...</programlisting>
+      </example>
+    </section>
+
+    <section>
+      <title>subscription_expires_range (int)</title>
+
+      <para>This parameter specifies that the expiry used for newly created
+      subscriptions are not fixed(when subscription_default_expires
+      applies), but a random value in the interval
+      [subscription_default_expires-subscription_expires_range%,
+      subscription_default_expires+subscription_expires_range%]. 
+      The value is between 0 and 100 and represent the maximim percentage 
+      from subscription_default_expires that will be substracted or added when 
+      computing the value. Default in 0, meaning subscription_default_expires is 
+      left unmodified.</para>
+
+      <para><emphasis> Default value is 0. </emphasis></para>
+
+      <example>
+        <title>Set <varname>subscription_expires_range </varname>parameter</title>
+
+        <programlisting format="linespecific">...
+        modparam("ims_registrar_scscf", "subscription_expires_range", 30) # +- 30% from subscription_expires_range
+...</programlisting>
+      </example>
+    </section>
+
+    <section>
+      <title>subscription_min_expires (int)</title>
+
+      <para>The minimum expires value of a subscription, values lower than this
+      minimum will be automatically set to the minimum. Value 0 disables the
+      checking.</para>
+
+      <para><emphasis> Default value is 10. </emphasis></para>
+
+      <example>
+        <title>Set <varname>subscription_min_expires</varname>parameter</title>
+
+        <programlisting format="linespecific">...
+        modparam("subscription_min_expires", "min_expires", 1800)
+...</programlisting>
+      </example>
+    </section>
+
+    <section>
+      <title>subscription_max_expires (int)</title>
+
+      <para>The maximum expires value of a subscription, values higher than this
+      maximum will be automatically set to the maximum. Value 0 disables the
+      checking.</para>
+
+      <para><emphasis> Default value is 1000000. </emphasis></para>
+
+      <example>
+        <title>Set <varname>subscription_max_expires</varname>parameter</title>
+
+        <programlisting format="linespecific">...
+        modparam("ims_registrar_scscf", "subscription_max_expires", 3600)
+...</programlisting>
+      </example>
+    </section>
 
     <section>
       <title>user_data_dtd (string)</title>

modules/ims_registrar_scscf/reg_mod.c

@@ -153,6 +153,7 @@ str sock_hdr_name = {0, 0};
 int subscription_default_expires = 3600; /**< the default value for expires if none found*/
 int subscription_min_expires = 10; /**< minimum subscription expiration time 		*/
 int subscription_max_expires = 1000000; /**< maximum subscription expiration time 		*/
+int subscription_expires_range = 0;
 
 
 extern reg_notification_list *notification_list; /**< list of notifications for reg to be sent			*/
@@ -246,6 +247,7 @@ static param_export_t params[] = {
     {"subscription_min_expires", INT_PARAM, &subscription_min_expires},
     {"subscription_max_expires", INT_PARAM, &subscription_max_expires},
     {"ue_unsubscribe_on_dereg", INT_PARAM, &ue_unsubscribe_on_dereg},
+    {"subscription_expires_range", INT_PARAM, &subscription_expires_range},
     {"user_data_always", INT_PARAM, &user_data_always},
 
     {0, 0, 0}

modules/ims_registrar_scscf/registrar_notify.c

@@ -91,6 +91,22 @@ static str ctype_hdr1 = {"Content-Type: ", 14};
 static str ctype_hdr2 = {"\r\n", 2};
 
 extern int ue_unsubscribe_on_dereg;
+extern int subscription_expires_range;
+
+/* \brief
+ * Return randomized expires between expires-range% and expires.
+ * RFC allows only value less or equal to the one provided by UAC.
+ */
+
+static inline int randomize_expires( int expires, int range )
+{
+	/* if no range is given just return expires */
+	if(range == 0) return expires;
+
+	int range_min = expires - (float)range/100 * expires;
+
+	return range_min + (float)(rand()%100)/100 * ( expires - range_min );
+}
 
 int notify_init() {
     notification_list = shm_malloc(sizeof (reg_notification_list));
@@ -1055,6 +1071,8 @@ int subscribe_to_reg(struct sip_msg *msg, char *_t, char *str2) {
 
         if (expires < subscription_min_expires) expires = subscription_min_expires;
         if (expires > subscription_max_expires) expires = subscription_max_expires;
+	
+	expires = randomize_expires(expires, subscription_expires_range);
 
         get_act_time();
         expires_time = expires + act_time;

modules/ims_registrar_scscf/save.c

@@ -86,6 +86,22 @@ extern int store_data_on_dereg; /**< should we store SAR user data on de-registr
 extern int ue_unsubscribe_on_dereg;
 extern int user_data_always;
 
+
+/* \brief
+ * Return randomized expires between expires-range% and expires.
+ * RFC allows only value less or equal to the one provided by UAC.
+ */
+static inline int randomize_expires( int expires, int range )
+{
+	/* if no range is given just return expires */
+	if(range == 0) return expires;
+
+	int range_min = expires - (float)range/100 * expires;
+
+	return range_min + (float)(rand()%100)/100 * ( expires - range_min );
+}
+
+
 /*! \brief
  * Calculate absolute expires value per contact as follows:
  * 1) If the contact has expires value, use the value. If it
@@ -124,6 +140,9 @@ static inline int calc_contact_expires(contact_t *c, unsigned int expires_hdr, i
         r = default_registrar_cfg.em_min_expires;
 
 end:
+	    
+    r = randomize_expires(r, default_registrar_cfg.default_expires_range);
+	    
     LM_DBG("Calculated expires for contact is %d\n", r);
     return time(NULL) + r;
 }