IPCP_HISADDR_SEEN
if (sp->ipcp.flags & IPCP_HISADDR_SEEN)
sp->ipcp.flags |= IPCP_HISADDR_SEEN;
if (rlen == 0 && !(sp->ipcp.flags & IPCP_HISADDR_SEEN)) {
sp->ipcp.flags &= ~(IPCP_HISADDR_SEEN|IPCP_MYADDR_SEEN|
(sp->ipcp.flags & IPCP_HISADDR_SEEN))