tnbr_new
tnbr = tnbr_new(leconf, af, src);
tnbr = tnbr_new(leconf, pw->af, &pw->addr);
struct tnbr *tnbr_new(struct ldpd_conf *, int, union ldpd_addr *);
t = tnbr_new(conf, af, addr);