// license that can be found in the LICENSE file.

package net

import (
	"os"
	"runtime"
	"syscall"
)

func setIPv4MulticastInterface(fd *netFD, ifi *Interface) error {
	ip, err := interfaceToIPv4Addr(ifi)
	if err != nil {
		return os.NewSyscallError("setsockopt", err)
	}
	var a [4]byte
	copy(a[:], ip.To4())
	err = fd.pfd.SetsockoptInet4Addr(syscall.IPPROTO_IP, syscall.IP_MULTICAST_IF, a)

//go:build aix || darwin || dragonfly || freebsd || netbsd || openbsd || solaris

package net

import (
	"runtime"
	"syscall"
)

func setIPv4MulticastInterface(fd *netFD, ifi *Interface) error {
	ip, err := interfaceToIPv4Addr(ifi)
	if err != nil {
		return wrapSyscallError("setsockopt", err)
	}
	var a [4]byte
	copy(a[:], ip.To4())
	err = fd.pfd.SetsockoptInet4Addr(syscall.IPPROTO_IP, syscall.IP_MULTICAST_IF, a)
	runtime.KeepAlive(fd)

//go:build unix || windows

package net

import (
	"internal/bytealg"
	"runtime"
	"syscall"
)

// Boolean to int.
func boolint(b bool) int {
	if b {
		return 1
	}
	return 0
}

func interfaceToIPv4Addr(ifi *Interface) (IP, error) {
	if ifi == nil {
		return IPv4zero, nil
	}
	ifat, err := ifi.Addrs()
	if err != nil {
		return nil, err
	}
	for _, ifa := range ifat {
		switch v := ifa.(type) {