make the ipv4 subnet matching code work like the ipv6 code, fixes bug in...

make the ipv4 subnet matching code work like the ipv6 code, fixes bug in subnet matching on tun interfaces

src/etc/inc/interfaces.lib.inc

@@ -246,8 +246,15 @@ function legacy_interfaces_details($intf = null)
             $result[$current_interface]["macaddr"] = $line_parts[1];
         } elseif (strpos($line, "\tinet ") !== false) {
             // IPv4 information
-            $mask = substr_count(base_convert(hexdec($line_parts[3]), 10, 2), '1');
-            $result[$current_interface]["ipv4"][] = array("ipaddr" => $line_parts[1], "subnetbits" => $mask);
+			unset($mask);
+            for ($i = 0; $i < count($line_parts) - 1; ++$i) {
+                if ($line_parts[$i] == 'netmask') {
+                    $mask = substr_count(base_convert(hexdec($line_parts[($i + 1)]), 10, 2), '1');
+                }
+            }
+            if (isset($mask)) {
+                $result[$current_interface]["ipv4"][] = array("ipaddr" => $line_parts[1], "subnetbits" => $mask);
+            }
         } elseif (strpos($line, "\tinet6 ") !== false) {
             // IPv6 information
             $addr = strtok($line_parts[1], '%');