}

func (a *IPAddr) toLocal(net string) sockaddr {
	return &IPAddr{loopbackIP(net), a.Zone}
}

func (c *IPConn) readFrom(b []byte) (int, *IPAddr, error) {
	// TODO(cw,rsc): consider using readv if we know the family
	// type to avoid the header trim/copy
	var addr *IPAddr
	n, sa, err := c.fd.readFrom(b)
	switch sa := sa.(type) {
	case *syscall.SockaddrInet4:
		addr = &IPAddr{IP: sa.Addr[0:]}