dnscrypt-proxy/vendor/golang.org/x/net/ipv4/sys_asmreqn.go

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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin freebsd linux
package ipv4
import (
"net"
"unsafe"
"golang.org/x/net/internal/socket"
)
func (so *sockOpt) getIPMreqn(c *socket.Conn) (*net.Interface, error) {
b := make([]byte, so.Len)
if _, err := so.Get(c, b); err != nil {
return nil, err
}
mreqn := (*ipMreqn)(unsafe.Pointer(&b[0]))
if mreqn.Ifindex == 0 {
return nil, nil
}
ifi, err := net.InterfaceByIndex(int(mreqn.Ifindex))
if err != nil {
return nil, err
}
return ifi, nil
}
func (so *sockOpt) setIPMreqn(c *socket.Conn, ifi *net.Interface, grp net.IP) error {
var mreqn ipMreqn
if ifi != nil {
mreqn.Ifindex = int32(ifi.Index)
}
if grp != nil {
mreqn.Multiaddr = [4]byte{grp[0], grp[1], grp[2], grp[3]}
}
b := (*[sizeofIPMreqn]byte)(unsafe.Pointer(&mreqn))[:sizeofIPMreqn]
return so.Set(c, b)
}