sockopt_posix.go

Documentation: net

     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 ipv4AddrToInterface(ip IP) (*Interface, error) {
    24  	ift, err := Interfaces()
    25  	if err != nil {
    26  		return nil, err
    27  	}
    28  	for _, ifi := range ift {
    29  		ifat, err := ifi.Addrs()
    30  		if err != nil {
    31  			return nil, err
    32  		}
    33  		for _, ifa := range ifat {
    34  			switch v := ifa.(type) {
    35  			case *IPAddr:
    36  				if ip.Equal(v.IP) {
    37  					return &ifi, nil
    38  				}
    39  			case *IPNet:
    40  				if ip.Equal(v.IP) {
    41  					return &ifi, nil
    42  				}
    43  			}
    44  		}
    45  	}
    46  	if ip.Equal(IPv4zero) {
    47  		return nil, nil
    48  	}
    49  	return nil, errNoSuchInterface
    50  }
    51  
    52  func interfaceToIPv4Addr(ifi *Interface) (IP, error) {
    53  	if ifi == nil {
    54  		return IPv4zero, nil
    55  	}
    56  	ifat, err := ifi.Addrs()
    57  	if err != nil {
    58  		return nil, err
    59  	}
    60  	for _, ifa := range ifat {
    61  		switch v := ifa.(type) {
    62  		case *IPAddr:
    63  			if v.IP.To4() != nil {
    64  				return v.IP, nil
    65  			}
    66  		case *IPNet:
    67  			if v.IP.To4() != nil {
    68  				return v.IP, nil
    69  			}
    70  		}
    71  	}
    72  	return nil, errNoSuchInterface
    73  }
    74  
    75  func setIPv4MreqToInterface(mreq *syscall.IPMreq, ifi *Interface) error {
    76  	if ifi == nil {
    77  		return nil
    78  	}
    79  	ifat, err := ifi.Addrs()
    80  	if err != nil {
    81  		return err
    82  	}
    83  	for _, ifa := range ifat {
    84  		switch v := ifa.(type) {
    85  		case *IPAddr:
    86  			if a := v.IP.To4(); a != nil {
    87  				copy(mreq.Interface[:], a)
    88  				goto done
    89  			}
    90  		case *IPNet:
    91  			if a := v.IP.To4(); a != nil {
    92  				copy(mreq.Interface[:], a)
    93  				goto done
    94  			}
    95  		}
    96  	}
    97  done:
    98  	if bytealg.Equal(mreq.Multiaddr[:], IPv4zero.To4()) {
    99  		return errNoSuchMulticastInterface
   100  	}
   101  	return nil
   102  }
   103  
   104  func setReadBuffer(fd *netFD, bytes int) error {
   105  	err := fd.pfd.SetsockoptInt(syscall.SOL_SOCKET, syscall.SO_RCVBUF, bytes)
   106  	runtime.KeepAlive(fd)
   107  	return wrapSyscallError("setsockopt", err)
   108  }
   109  
   110  func setWriteBuffer(fd *netFD, bytes int) error {
   111  	err := fd.pfd.SetsockoptInt(syscall.SOL_SOCKET, syscall.SO_SNDBUF, bytes)
   112  	runtime.KeepAlive(fd)
   113  	return wrapSyscallError("setsockopt", err)
   114  }
   115  
   116  func setKeepAlive(fd *netFD, keepalive bool) error {
   117  	err := fd.pfd.SetsockoptInt(syscall.SOL_SOCKET, syscall.SO_KEEPALIVE, boolint(keepalive))
   118  	runtime.KeepAlive(fd)
   119  	return wrapSyscallError("setsockopt", err)
   120  }
   121  
   122  func setLinger(fd *netFD, sec int) error {
   123  	var l syscall.Linger
   124  	if sec >= 0 {
   125  		l.Onoff = 1
   126  		l.Linger = int32(sec)
   127  	} else {
   128  		l.Onoff = 0
   129  		l.Linger = 0
   130  	}
   131  	err := fd.pfd.SetsockoptLinger(syscall.SOL_SOCKET, syscall.SO_LINGER, &l)
   132  	runtime.KeepAlive(fd)
   133  	return wrapSyscallError("setsockopt", err)
   134  }
   135
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