sockopt_posix.go

     1  // Copyright 2009 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 unix || windows
     6  
     7  package net
     8  
     9  import (
    10  	"internal/bytealg"
    11  	"runtime"
    12  	"syscall"
    13  )
    14  
    15  // Boolean to int.
    16  func boolint(b bool) int {
    17  	if b {
    18  		return 1
    19  	}
    20  	return 0
    21  }
    22  
    23  func interfaceToIPv4Addr(ifi *Interface) (IP, error) {
    24  	if ifi == nil {
    25  		return IPv4zero, nil
    26  	}
    27  	ifat, err := ifi.Addrs()
    28  	if err != nil {
    29  		return nil, err
    30  	}
    31  	for _, ifa := range ifat {
    32  		switch v := ifa.(type) {
    33  		case *IPAddr:
    34  			if v.IP.To4() != nil {
    35  				return v.IP, nil
    36  			}
    37  		case *IPNet:
    38  			if v.IP.To4() != nil {
    39  				return v.IP, nil
    40  			}
    41  		}
    42  	}
    43  	return nil, errNoSuchInterface
    44  }
    45  
    46  func setIPv4MreqToInterface(mreq *syscall.IPMreq, ifi *Interface) error {
    47  	if ifi == nil {
    48  		return nil
    49  	}
    50  	ifat, err := ifi.Addrs()
    51  	if err != nil {
    52  		return err
    53  	}
    54  	for _, ifa := range ifat {
    55  		switch v := ifa.(type) {
    56  		case *IPAddr:
    57  			if a := v.IP.To4(); a != nil {
    58  				copy(mreq.Interface[:], a)
    59  				goto done
    60  			}
    61  		case *IPNet:
    62  			if a := v.IP.To4(); a != nil {
    63  				copy(mreq.Interface[:], a)
    64  				goto done
    65  			}
    66  		}
    67  	}
    68  done:
    69  	if bytealg.Equal(mreq.Multiaddr[:], IPv4zero.To4()) {
    70  		return errNoSuchMulticastInterface
    71  	}
    72  	return nil
    73  }
    74  
    75  func setReadBuffer(fd *netFD, bytes int) error {
    76  	err := fd.pfd.SetsockoptInt(syscall.SOL_SOCKET, syscall.SO_RCVBUF, bytes)
    77  	runtime.KeepAlive(fd)
    78  	return wrapSyscallError("setsockopt", err)
    79  }
    80  
    81  func setWriteBuffer(fd *netFD, bytes int) error {
    82  	err := fd.pfd.SetsockoptInt(syscall.SOL_SOCKET, syscall.SO_SNDBUF, bytes)
    83  	runtime.KeepAlive(fd)
    84  	return wrapSyscallError("setsockopt", err)
    85  }
    86  
    87  func setKeepAlive(fd *netFD, keepalive bool) error {
    88  	err := fd.pfd.SetsockoptInt(syscall.SOL_SOCKET, syscall.SO_KEEPALIVE, boolint(keepalive))
    89  	runtime.KeepAlive(fd)
    90  	return wrapSyscallError("setsockopt", err)
    91  }
    92  
    93  func setLinger(fd *netFD, sec int) error {
    94  	var l syscall.Linger
    95  	if sec >= 0 {
    96  		l.Onoff = 1
    97  		l.Linger = int32(sec)
    98  	} else {
    99  		l.Onoff = 0
   100  		l.Linger = 0
   101  	}
   102  	err := fd.pfd.SetsockoptLinger(syscall.SOL_SOCKET, syscall.SO_LINGER, &l)
   103  	runtime.KeepAlive(fd)
   104  	return wrapSyscallError("setsockopt", err)
   105  }
   106
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