radius_get_mppe_recv_key_attr
int radius_get_mppe_recv_key_attr(const RADIUS_PACKET *,
if (radius_get_mppe_recv_key_attr(packet, buf0, &len0, secret) == 0 &&
CHECK(radius_get_mppe_recv_key_attr(response, plain, &plen, "sharedsecret") == 0);