sys_unix.go raw

   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  //go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
   6  
   7  package socket
   8  
   9  import (
  10  	"net"
  11  	"unsafe"
  12  
  13  	"golang.org/x/sys/unix"
  14  )
  15  
  16  //go:linkname syscall_getsockopt syscall.getsockopt
  17  func syscall_getsockopt(s, level, name int, val unsafe.Pointer, vallen *uint32) error
  18  
  19  //go:linkname syscall_setsockopt syscall.setsockopt
  20  func syscall_setsockopt(s, level, name int, val unsafe.Pointer, vallen uintptr) error
  21  
  22  func getsockopt(s uintptr, level, name int, b []byte) (int, error) {
  23  	l := uint32(len(b))
  24  	err := syscall_getsockopt(int(s), level, name, unsafe.Pointer(&b[0]), &l)
  25  	return int(l), err
  26  }
  27  
  28  func setsockopt(s uintptr, level, name int, b []byte) error {
  29  	return syscall_setsockopt(int(s), level, name, unsafe.Pointer(&b[0]), uintptr(len(b)))
  30  }
  31  
  32  func recvmsg(s uintptr, buffers [][]byte, oob []byte, flags int, network string) (n, oobn int, recvflags int, from net.Addr, err error) {
  33  	var unixFrom unix.Sockaddr
  34  	n, oobn, recvflags, unixFrom, err = unix.RecvmsgBuffers(int(s), buffers, oob, flags)
  35  	if unixFrom != nil {
  36  		from = sockaddrToAddr(unixFrom, network)
  37  	}
  38  	return
  39  }
  40  
  41  func sendmsg(s uintptr, buffers [][]byte, oob []byte, to net.Addr, flags int) (int, error) {
  42  	var unixTo unix.Sockaddr
  43  	if to != nil {
  44  		unixTo = addrToSockaddr(to)
  45  	}
  46  	return unix.SendmsgBuffers(int(s), buffers, oob, unixTo, flags)
  47  }
  48  
  49  // addrToSockaddr converts a net.Addr to a unix.Sockaddr.
  50  func addrToSockaddr(a net.Addr) unix.Sockaddr {
  51  	var (
  52  		ip   net.IP
  53  		port int
  54  		zone string
  55  	)
  56  	switch a := a.(type) {
  57  	case *net.TCPAddr:
  58  		ip = a.IP
  59  		port = a.Port
  60  		zone = a.Zone
  61  	case *net.UDPAddr:
  62  		ip = a.IP
  63  		port = a.Port
  64  		zone = a.Zone
  65  	case *net.IPAddr:
  66  		ip = a.IP
  67  		zone = a.Zone
  68  	default:
  69  		return nil
  70  	}
  71  
  72  	if ip4 := ip.To4(); ip4 != nil {
  73  		sa := unix.SockaddrInet4{Port: port}
  74  		copy(sa.Addr[:], ip4)
  75  		return &sa
  76  	}
  77  
  78  	if ip6 := ip.To16(); ip6 != nil && ip.To4() == nil {
  79  		sa := unix.SockaddrInet6{Port: port}
  80  		copy(sa.Addr[:], ip6)
  81  		if zone != "" {
  82  			sa.ZoneId = uint32(zoneCache.index(zone))
  83  		}
  84  		return &sa
  85  	}
  86  
  87  	return nil
  88  }
  89  
  90  // sockaddrToAddr converts a unix.Sockaddr to a net.Addr.
  91  func sockaddrToAddr(sa unix.Sockaddr, network string) net.Addr {
  92  	var (
  93  		ip   net.IP
  94  		port int
  95  		zone string
  96  	)
  97  	switch sa := sa.(type) {
  98  	case *unix.SockaddrInet4:
  99  		ip = make(net.IP, net.IPv4len)
 100  		copy(ip, sa.Addr[:])
 101  		port = sa.Port
 102  	case *unix.SockaddrInet6:
 103  		ip = make(net.IP, net.IPv6len)
 104  		copy(ip, sa.Addr[:])
 105  		port = sa.Port
 106  		if sa.ZoneId > 0 {
 107  			zone = zoneCache.name(int(sa.ZoneId))
 108  		}
 109  	default:
 110  		return nil
 111  	}
 112  
 113  	switch network {
 114  	case "tcp", "tcp4", "tcp6":
 115  		return &net.TCPAddr{IP: ip, Port: port, Zone: zone}
 116  	case "udp", "udp4", "udp6":
 117  		return &net.UDPAddr{IP: ip, Port: port, Zone: zone}
 118  	default:
 119  		return &net.IPAddr{IP: ip, Zone: zone}
 120  	}
 121  }
 122