github.com/c12o16h1/go/src@v0.0.0-20200114212001-5a151c0f00ed/net/rawconn_unix_test.go (about)

     1  // Copyright 2017 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 aix darwin dragonfly freebsd linux netbsd openbsd solaris
     6  
     7  package net
     8  
     9  import (
    10  	"errors"
    11  	"syscall"
    12  )
    13  
    14  func readRawConn(c syscall.RawConn, b []byte) (int, error) {
    15  	var operr error
    16  	var n int
    17  	err := c.Read(func(s uintptr) bool {
    18  		n, operr = syscall.Read(int(s), b)
    19  		if operr == syscall.EAGAIN {
    20  			return false
    21  		}
    22  		return true
    23  	})
    24  	if err != nil {
    25  		return n, err
    26  	}
    27  	if operr != nil {
    28  		return n, operr
    29  	}
    30  	return n, nil
    31  }
    32  
    33  func writeRawConn(c syscall.RawConn, b []byte) error {
    34  	var operr error
    35  	err := c.Write(func(s uintptr) bool {
    36  		_, operr = syscall.Write(int(s), b)
    37  		if operr == syscall.EAGAIN {
    38  			return false
    39  		}
    40  		return true
    41  	})
    42  	if err != nil {
    43  		return err
    44  	}
    45  	if operr != nil {
    46  		return operr
    47  	}
    48  	return nil
    49  }
    50  
    51  func controlRawConn(c syscall.RawConn, addr Addr) error {
    52  	var operr error
    53  	fn := func(s uintptr) {
    54  		_, operr = syscall.GetsockoptInt(int(s), syscall.SOL_SOCKET, syscall.SO_REUSEADDR)
    55  		if operr != nil {
    56  			return
    57  		}
    58  		switch addr := addr.(type) {
    59  		case *TCPAddr:
    60  			// There's no guarantee that IP-level socket
    61  			// options work well with dual stack sockets.
    62  			// A simple solution would be to take a look
    63  			// at the bound address to the raw connection
    64  			// and to classify the address family of the
    65  			// underlying socket by the bound address:
    66  			//
    67  			// - When IP.To16() != nil and IP.To4() == nil,
    68  			//   we can assume that the raw connection
    69  			//   consists of an IPv6 socket using only
    70  			//   IPv6 addresses.
    71  			//
    72  			// - When IP.To16() == nil and IP.To4() != nil,
    73  			//   the raw connection consists of an IPv4
    74  			//   socket using only IPv4 addresses.
    75  			//
    76  			// - Otherwise, the raw connection is a dual
    77  			//   stack socket, an IPv6 socket using IPv6
    78  			//   addresses including IPv4-mapped or
    79  			//   IPv4-embedded IPv6 addresses.
    80  			if addr.IP.To16() != nil && addr.IP.To4() == nil {
    81  				operr = syscall.SetsockoptInt(int(s), syscall.IPPROTO_IPV6, syscall.IPV6_UNICAST_HOPS, 1)
    82  			} else if addr.IP.To16() == nil && addr.IP.To4() != nil {
    83  				operr = syscall.SetsockoptInt(int(s), syscall.IPPROTO_IP, syscall.IP_TTL, 1)
    84  			}
    85  		}
    86  	}
    87  	if err := c.Control(fn); err != nil {
    88  		return err
    89  	}
    90  	if operr != nil {
    91  		return operr
    92  	}
    93  	return nil
    94  }
    95  
    96  func controlOnConnSetup(network string, address string, c syscall.RawConn) error {
    97  	var operr error
    98  	var fn func(uintptr)
    99  	switch network {
   100  	case "tcp", "udp", "ip":
   101  		return errors.New("ambiguous network: " + network)
   102  	case "unix", "unixpacket", "unixgram":
   103  		fn = func(s uintptr) {
   104  			_, operr = syscall.GetsockoptInt(int(s), syscall.SOL_SOCKET, syscall.SO_ERROR)
   105  		}
   106  	default:
   107  		switch network[len(network)-1] {
   108  		case '4':
   109  			fn = func(s uintptr) {
   110  				operr = syscall.SetsockoptInt(int(s), syscall.IPPROTO_IP, syscall.IP_TTL, 1)
   111  			}
   112  		case '6':
   113  			fn = func(s uintptr) {
   114  				operr = syscall.SetsockoptInt(int(s), syscall.IPPROTO_IPV6, syscall.IPV6_UNICAST_HOPS, 1)
   115  			}
   116  		default:
   117  			return errors.New("unknown network: " + network)
   118  		}
   119  	}
   120  	if err := c.Control(fn); err != nil {
   121  		return err
   122  	}
   123  	if operr != nil {
   124  		return operr
   125  	}
   126  	return nil
   127  }