}
	buf = buf[:m]

	h, buf := unmarshalUDPHeader(buf)
	n := copy(b, buf)
	*addr = UDPAddr{IP: h.raddr, Port: int(h.rport)}
	return n, addr, nil
}

func (c *UDPConn) readFromAddrPort(b []byte) (int, netip.AddrPort, error) {
	// TODO: optimize. The equivalent code on posix is alloc-free.
	buf := make([]byte, udpHeaderSize+len(b))
	m, err := c.fd.Read(buf)
	if err != nil {

		}
	}
	if err != nil {
		// No sockaddr, so don't return UDPAddr.
		addr = nil
	}
	return n, addr, err
}

func (c *UDPConn) readFromAddrPort(b []byte) (n int, addr netip.AddrPort, err error) {
	var ip netip.Addr
	var port int
	switch c.fd.family {
	case syscall.AF_INET:
		var from syscall.SockaddrInet4
		n, err = c.fd.readFromInet4(b, &from)

func (c *UDPConn) ReadFromUDPAddrPort(b []byte) (n int, addr netip.AddrPort, err error) {
	if !c.ok() {
		return 0, netip.AddrPort{}, syscall.EINVAL
	}
	n, addr, err = c.readFromAddrPort(b)
	if err != nil {
		err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
	}
	return n, addr, err
}