DHCHAP_CHALL_NULL
tmp += sizeof (DHCHAP_CHALL_NULL);
DHCHAP_CHALL_NULL *ncval;
ncval = (DHCHAP_CHALL_NULL *)((uint8_t *)lp);
tmp = (uint8_t *)((uint8_t *)lp + sizeof (DHCHAP_CHALL_NULL));
DHCHAP_CHALL_NULL cnul;