github.com/graybobo/golang.org-package-offline-cache@v0.0.0-20200626051047-6608995c132f/x/net/ipv4/sockopt_asmreqn_unix.go (about)

     1  // Copyright 2014 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build darwin freebsd linux
     6  
     7  package ipv4
     8  
     9  import (
    10  	"net"
    11  	"os"
    12  	"unsafe"
    13  
    14  	"golang.org/x/net/internal/iana"
    15  )
    16  
    17  func getsockoptIPMreqn(fd, name int) (*net.Interface, error) {
    18  	var mreqn sysIPMreqn
    19  	l := sysSockoptLen(sysSizeofIPMreqn)
    20  	if err := getsockopt(fd, iana.ProtocolIP, name, unsafe.Pointer(&mreqn), &l); err != nil {
    21  		return nil, os.NewSyscallError("getsockopt", err)
    22  	}
    23  	if mreqn.Ifindex == 0 {
    24  		return nil, nil
    25  	}
    26  	ifi, err := net.InterfaceByIndex(int(mreqn.Ifindex))
    27  	if err != nil {
    28  		return nil, err
    29  	}
    30  	return ifi, nil
    31  }
    32  
    33  func setsockoptIPMreqn(fd, name int, ifi *net.Interface, grp net.IP) error {
    34  	var mreqn sysIPMreqn
    35  	if ifi != nil {
    36  		mreqn.Ifindex = int32(ifi.Index)
    37  	}
    38  	if grp != nil {
    39  		mreqn.Multiaddr = [4]byte{grp[0], grp[1], grp[2], grp[3]}
    40  	}
    41  	return os.NewSyscallError("setsockopt", setsockopt(fd, iana.ProtocolIP, name, unsafe.Pointer(&mreqn), sysSizeofIPMreqn))
    42  }