nhop_addrs
struct nhop_addrs na;
addrs_len = sizeof(struct nhop_addrs);
arpc.rtm.rtm_msglen += arpc.na.na_len - sizeof(struct nhop_addrs);
struct nhop_addrs *na;
na = (struct nhop_addrs *)((char *)nh + nh->nh_len);
struct nhop_addrs *na;
na = (struct nhop_addrs *)((char *)nh + nh->nh_len);