rc: align the behaviour of IPv4 and IPv6 IP renewal

PR: https://github.com/opnsense/core/pull/1524

src/etc/rc.newwanip

@@ -94,11 +94,7 @@ if ($curwanip == "0.0.0.0" || !is_ipaddr($curwanip)) {
     }
 }
 
-if (file_exists("/var/db/{$interface}_cacheip")) {
-    $oldip = file_get_contents("/var/db/{$interface}_cacheip");
-} else {
-    $oldip = "0.0.0.0";
-}
+$oldip = @file_get_contents("/var/db/{$interface}_cacheip");
 
 system_resolvconf_generate();
 

src/etc/rc.newwanipv6

@@ -83,12 +83,12 @@ if (!empty($new_domain_name_servers)) {
     }
 
     if (count($valid_ns) > 0) {
-        file_put_contents("/var/etc/nameserver_v6{$interface}", implode("\n", $valid_ns));
+        @file_put_contents("/var/etc/nameserver_v6{$interface}", implode("\n", $valid_ns));
     }
 }
 $new_domain_name = getenv("new_domain_name");
 if (!empty($new_domain_name)) {
-    file_put_contents("/var/etc/searchdomain_v6{$interface}", $new_domain_name);
+    @file_put_contents("/var/etc/searchdomain_v6{$interface}", $new_domain_name);
 }
 
 /* write current WAN IPv6 to file */
@@ -98,10 +98,7 @@ if (is_ipaddrv6($curwanipv6)) {
 
 log_error("rc.newwanipv6: on (IP address: {$curwanipv6}) (interface: {$interface}) (real interface: {$interface_real}).");
 
-$oldipv6 = "";
-if (file_exists("/var/db/{$interface}_cacheipv6")) {
-    $oldipv6 = file_get_contents("/var/db/{$interface}_cacheipv6");
-}
+$oldipv6 = @file_get_contents("/var/db/{$interface}_cacheipv6");
 
 $grouptmp = link_interface_to_group($interface);
 if (!empty($grouptmp)) {
@@ -110,30 +107,32 @@ if (!empty($grouptmp)) {
 
 link_interface_to_track6($interface, "update");
 system_resolvconf_generate();
-system_routing_configure($interface);
-setup_gateways_monitor();
-
-/* signal filter reload */
-filter_configure();
-
-if (is_ipaddrv6($oldipv6)) {
-    if ($curwanipv6 == $oldipv6) {
-        // Still need to sync VPNs on PPPoE and such, as even with the same IP the VPN software is unhappy with the IP disappearing.
-        if (in_array($config['interfaces'][$interface]['ipaddrv6'], array('pppoe', 'pptp', 'ppp'))) {
-            /* XXX migrate this: we should unify the reload */
-            ipsec_configure_do(false, $inteface);
-            openvpn_configure_do(false, $interface);
-        }
-        return;
-    } elseif (does_interface_exist($interface_real)) {
+
+/*
+ * We need to force sync VPNs on such even when the IP is the same for dynamic interfaces.
+ * Even with the same IP the VPN software is unhappy with the IP disappearing, and we
+ * could be failing back in which case we need to switch IPs back anyhow.
+ */
+if (!is_ipaddr($oldipv6) || $curwanipv6 != $oldipv6 || !is_ipaddrv6($config['interfaces'][$interface]['ipaddrv6'])) {
+    system_routing_configure($interface);
+    setup_gateways_monitor();
+
+    if (is_ipaddrv6($oldipv6)) {
+        if (does_interface_exist($interface_real)) {
             mwexec("/sbin/ifconfig {$interface_real} inet6 {$oldipv6} delete");
         }
+    }
 
-    file_put_contents("/var/db/{$interface}_cacheipv6", $curwanipv6);
-}
+    if (is_ipaddrv6($curwanip)) {
+        @file_put_contents("/var/db/{$interface}_cacheipv6", $curwanipv6);
+    }
+
+    /* reload plugins */
+    plugins_configure('interface', false, array($interface));
 
-/* reload plugins */
-plugins_configure('interface', false, array($interface));
+    /* reload graphing functions */
+    rrd_configure();
+}
 
-/* reload graphing functions */
-rrd_configure();
+/* reload filter, don't try to sync to carp slave */
+filter_configure_sync();