// described in RFC 2782.
func (addrs byPriorityWeight) shuffleByWeight() {
	sum := 0
	for _, addr := range addrs {
		sum += int(addr.Weight)
	}
	for sum > 0 && len(addrs) > 1 {
		s := 0
		n := randIntn(sum)
		for i := range addrs {
			s += int(addrs[i].Weight)
			if s > n {
				if i > 0 {
					addrs[0], addrs[i] = addrs[i], addrs[0]
				}
				break
			}
		}

	}

	addr = tcpAddr
	return addr
}

// Addrs - returns all address information of TCP listeners.
func (listener *httpListener) Addrs() (addrs []net.Addr) {
	for i := range listener.listeners {
		addrs = append(addrs, listener.listeners[i].Addr())
	}

	return addrs
}

// TCPOptions specify customizable TCP optimizations on raw socket
type TCPOptions struct {

	"net/netip"
	"sort"
)

func sortByRFC6724(addrs []IPAddr) {
	if len(addrs) < 2 {
		return
	}
	sortByRFC6724withSrcs(addrs, srcAddrs(addrs))
}

func sortByRFC6724withSrcs(addrs []IPAddr, srcs []netip.Addr) {
	if len(addrs) != len(srcs) {
		panic("internal error")
	}
	addrAttr := make([]ipAttr, len(addrs))
	srcAttr := make([]ipAttr, len(srcs))
	for i, v := range addrs {
		addrAttrIP, _ := netip.AddrFromSlice(v.IP)

	// Partition addresses into two sets: ones with a known object file, and ones without.
	var addrs, unprocessed []uint64
	for addr, info := range addrMap {
		if info.obj != nil {
			addrs = append(addrs, addr)
		} else {
			unprocessed = append(unprocessed, addr)
		}
	}
	sort.Slice(addrs, func(i, j int) bool { return addrs[i] < addrs[j] })

	const expand = 500 // How much to expand range to pick up nearby addresses.

			sa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(*_C_ai_addr(r)))
			addr := IPAddr{IP: copyIP(sa.Addr[:])}
			addrs = append(addrs, addr)
		case _C_AF_INET6:
			sa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(*_C_ai_addr(r)))
			addr := IPAddr{IP: copyIP(sa.Addr[:]), Zone: zoneCache.name(int(sa.Scope_id))}
			addrs = append(addrs, addr)
		}
	}
	return addrs, nil
}

				mask = CIDRMask(pfxlen, 8*IPv6len)
			}

			addrs = append(addrs, &IPNet{IP: ip, Mask: mask})
		}
	}

	return addrs, nil
}

// interfaceMulticastAddrTable returns addresses for a specific
// interface.
func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
	return nil, nil

	if err != nil {
		return nil, err
	}
	addrs := addrsi.([]IPAddr)
	if shared {
		clone := make([]IPAddr, len(addrs))
		copy(clone, addrs)
		addrs = clone
	}
	return addrs, nil
}

// ipAddrsEface returns an empty interface slice of addrs.
func ipAddrsEface(addrs []IPAddr) []any {
	s := make([]any, len(addrs))
	for i, v := range addrs {
		s[i] = v
	}
	return s
}

	if interfaces, err = net.Interfaces(); err != nil {
		return false, fmt.Errorf("failed to get interfaces")
	}

	for _, ief := range interfaces {
		var addrs []net.Addr
		if addrs, err = ief.Addrs(); err != nil {
			return
		}
		for _, addr := range addrs {
			switch v := addr.(type) {
			case *net.IPNet:
				if v.IP.Equal(targetAddr) {
					return true, nil
				}
			}
		}
	}

		s = "0"
	}
	return s
}

// Addrs returns a list of unicast interface addresses for a specific
// interface.
func (ifi *Interface) Addrs() ([]Addr, error) {
	if ifi == nil {
		return nil, &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: errInvalidInterface}
	}
	ifat, err := interfaceAddrTable(ifi)
	if err != nil {
		err = &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: err}
	}
	return ifat, err

func AppendPortIfNeeded(addr string, port int32) string {
	// Return if address is already in "ipv4:port" or "[ipv6]:port" format.
	if _, _, err := net.SplitHostPort(addr); err == nil {
		return addr
	}

	// Simply return for invalid case. This should be caught by validation instead.
	ip := netutils.ParseIPSloppy(addr)
	if ip == nil {
		return addr
	}

	// Append port to address.