+ /*
+ * RFC 4941 section 3.3:
+ * If a received option will extend the lifetime
+ * of a public address, the lifetimes of
+ * temporary addresses should be extended,
+ * subject to the overall constraint that no
+ * temporary addresses should ever remain
+ * "valid" or "preferred" for a time longer than
+ * (TEMP_VALID_LIFETIME) or
+ * (TEMP_PREFERRED_LIFETIME - DESYNC_FACTOR),
+ * respectively.
+ */
+ age = (now - ift->cstamp) / HZ;
+ max_valid = in6_dev->cnf.temp_valid_lft - age;
+ if (max_valid < 0)
+ max_valid = 0;
+
+ max_prefered = in6_dev->cnf.temp_prefered_lft -
+ in6_dev->cnf.max_desync_factor -
+ age;
+ if (max_prefered < 0)
+ max_prefered = 0;
+
+ if (valid_lft > max_valid)
+ valid_lft = max_valid;
+
+ if (prefered_lft > max_prefered)
+ prefered_lft = max_prefered;
+