addr_netmask
if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1)
if (addr_netmask(a->af, masklen, &tmp_mask) == -1)
if (addr_netmask(host->af, masklen, &tmp_mask) == -1)
int addr_netmask(int af, u_int l, struct xaddr *n);
if (addr_netmask(addr->af, bits, &xmask) != 0 ||