sys_asmreqn.go raw

   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  //go:build darwin || freebsd || linux
   6  
   7  package ipv4
   8  
   9  import (
  10  	"net"
  11  	"unsafe"
  12  
  13  	"golang.org/x/net/internal/socket"
  14  
  15  	"golang.org/x/sys/unix"
  16  )
  17  
  18  func (so *sockOpt) getIPMreqn(c *socket.Conn) (*net.Interface, error) {
  19  	b := make([]byte, so.Len)
  20  	if _, err := so.Get(c, b); err != nil {
  21  		return nil, err
  22  	}
  23  	mreqn := (*unix.IPMreqn)(unsafe.Pointer(&b[0]))
  24  	if mreqn.Ifindex == 0 {
  25  		return nil, nil
  26  	}
  27  	ifi, err := net.InterfaceByIndex(int(mreqn.Ifindex))
  28  	if err != nil {
  29  		return nil, err
  30  	}
  31  	return ifi, nil
  32  }
  33  
  34  func (so *sockOpt) setIPMreqn(c *socket.Conn, ifi *net.Interface, grp net.IP) error {
  35  	var mreqn unix.IPMreqn
  36  	if ifi != nil {
  37  		mreqn.Ifindex = int32(ifi.Index)
  38  	}
  39  	if grp != nil {
  40  		mreqn.Multiaddr = [4]byte{grp[0], grp[1], grp[2], grp[3]}
  41  	}
  42  	b := (*[unix.SizeofIPMreqn]byte)(unsafe.Pointer(&mreqn))[:unix.SizeofIPMreqn]
  43  	return so.Set(c, b)
  44  }
  45