nathelper: added carrier grade nat address space (rfc6598)

modules/nathelper/nathelper.c

@@ -328,6 +328,7 @@ static struct {
 	{"10.0.0.0",    0, 0xffffffffu << 24},
 	{"172.16.0.0",  0, 0xffffffffu << 20},
 	{"192.168.0.0", 0, 0xffffffffu << 16},
+	{"100.64.0.0",  0, 0xffffffffu << 22}, /* rfc6598 - cg-nat */
 	{NULL, 0, 0}
 };