libgo/go/net/interface_windows.go

   1 // Copyright 2011 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 package net
   6
   7 import (
   8         "internal/syscall/windows"
   9         "os"
  10         "syscall"
  11         "unsafe"
  12 )
  13
  14 // supportsVistaIP reports whether the platform implements new IP
  15 // stack and ABIs supported on Windows Vista and above.
  16 var supportsVistaIP bool
  17
  18 func init() {
  19         supportsVistaIP = probeWindowsIPStack()
  20 }
  21
  22 func probeWindowsIPStack() (supportsVistaIP bool) {
  23         v, err := syscall.GetVersion()
  24         if err != nil {
  25                 return true // Windows 10 and above will deprecate this API
  26         }
  27         return byte(v) >= 6 // major version of Windows Vista is 6
  28 }
  29
  30 // adapterAddresses returns a list of IP adapter and address
  31 // structures. The structure contains an IP adapter and flattened
  32 // multiple IP addresses including unicast, anycast and multicast
  33 // addresses.
  34 func adapterAddresses() ([]*windows.IpAdapterAddresses, error) {
  35         var b []byte
  36         l := uint32(15000) // recommended initial size
  37         for {
  38                 b = make([]byte, l)
  39                 err := windows.GetAdaptersAddresses(syscall.AF_UNSPEC, windows.GAA_FLAG_INCLUDE_PREFIX, 0, (*windows.IpAdapterAddresses)(unsafe.Pointer(&b[0])), &l)
  40                 if err == nil {
  41                         if l == 0 {
  42                                 return nil, nil
  43                         }
  44                         break
  45                 }
  46                 if err.(syscall.Errno) != syscall.ERROR_BUFFER_OVERFLOW {
  47                         return nil, os.NewSyscallError("getadaptersaddresses", err)
  48                 }
  49                 if l <= uint32(len(b)) {
  50                         return nil, os.NewSyscallError("getadaptersaddresses", err)
  51                 }
  52         }
  53         var aas []*windows.IpAdapterAddresses
  54         for aa := (*windows.IpAdapterAddresses)(unsafe.Pointer(&b[0])); aa != nil; aa = aa.Next {
  55                 aas = append(aas, aa)
  56         }
  57         return aas, nil
  58 }
  59
  60 // If the ifindex is zero, interfaceTable returns mappings of all
  61 // network interfaces. Otherwise it returns a mapping of a specific
  62 // interface.
  63 func interfaceTable(ifindex int) ([]Interface, error) {
  64         aas, err := adapterAddresses()
  65         if err != nil {
  66                 return nil, err
  67         }
  68         var ift []Interface
  69         for _, aa := range aas {
  70                 index := aa.IfIndex
  71                 if index == 0 { // ipv6IfIndex is a substitute for ifIndex
  72                         index = aa.Ipv6IfIndex
  73                 }
  74                 if ifindex == 0 || ifindex == int(index) {
  75                         ifi := Interface{
  76                                 Index: int(index),
  77                                 Name:  syscall.UTF16ToString((*(*[10000]uint16)(unsafe.Pointer(aa.FriendlyName)))[:]),
  78                         }
  79                         if aa.OperStatus == windows.IfOperStatusUp {
  80                                 ifi.Flags |= FlagUp
  81                         }
  82                         // For now we need to infer link-layer service
  83                         // capabilities from media types.
  84                         // We will be able to use
  85                         // MIB_IF_ROW2.AccessType once we drop support
  86                         // for Windows XP.
  87                         switch aa.IfType {
  88                         case windows.IF_TYPE_ETHERNET_CSMACD, windows.IF_TYPE_ISO88025_TOKENRING, windows.IF_TYPE_IEEE80211, windows.IF_TYPE_IEEE1394:
  89                                 ifi.Flags |= FlagBroadcast | FlagMulticast
  90                         case windows.IF_TYPE_PPP, windows.IF_TYPE_TUNNEL:
  91                                 ifi.Flags |= FlagPointToPoint | FlagMulticast
  92                         case windows.IF_TYPE_SOFTWARE_LOOPBACK:
  93                                 ifi.Flags |= FlagLoopback | FlagMulticast
  94                         case windows.IF_TYPE_ATM:
  95                                 ifi.Flags |= FlagBroadcast | FlagPointToPoint | FlagMulticast // assume all services available; LANE, point-to-point and point-to-multipoint
  96                         }
  97                         if aa.Mtu == 0xffffffff {
  98                                 ifi.MTU = -1
  99                         } else {
 100                                 ifi.MTU = int(aa.Mtu)
 101                         }
 102                         if aa.PhysicalAddressLength > 0 {
 103                                 ifi.HardwareAddr = make(HardwareAddr, aa.PhysicalAddressLength)
 104                                 copy(ifi.HardwareAddr, aa.PhysicalAddress[:])
 105                         }
 106                         ift = append(ift, ifi)
 107                         if ifindex == ifi.Index {
 108                                 break
 109                         }
 110                 }
 111         }
 112         return ift, nil
 113 }
 114
 115 // If the ifi is nil, interfaceAddrTable returns addresses for all
 116 // network interfaces. Otherwise it returns addresses for a specific
 117 // interface.
 118 func interfaceAddrTable(ifi *Interface) ([]Addr, error) {
 119         aas, err := adapterAddresses()
 120         if err != nil {
 121                 return nil, err
 122         }
 123         var ifat []Addr
 124         for _, aa := range aas {
 125                 index := aa.IfIndex
 126                 if index == 0 { // ipv6IfIndex is a substitute for ifIndex
 127                         index = aa.Ipv6IfIndex
 128                 }
 129                 var pfx4, pfx6 []IPNet
 130                 if !supportsVistaIP {
 131                         pfx4, pfx6, err = addrPrefixTable(aa)
 132                         if err != nil {
 133                                 return nil, err
 134                         }
 135                 }
 136                 if ifi == nil || ifi.Index == int(index) {
 137                         for puni := aa.FirstUnicastAddress; puni != nil; puni = puni.Next {
 138                                 sa, err := puni.Address.Sockaddr.Sockaddr()
 139                                 if err != nil {
 140                                         return nil, os.NewSyscallError("sockaddr", err)
 141                                 }
 142                                 var l int
 143                                 switch sa := sa.(type) {
 144                                 case *syscall.SockaddrInet4:
 145                                         if supportsVistaIP {
 146                                                 l = int(puni.OnLinkPrefixLength)
 147                                         } else {
 148                                                 l = addrPrefixLen(pfx4, IP(sa.Addr[:]))
 149                                         }
 150                                         ifat = append(ifat, &IPNet{IP: IPv4(sa.Addr[0], sa.Addr[1], sa.Addr[2], sa.Addr[3]), Mask: CIDRMask(l, 8*IPv4len)})
 151                                 case *syscall.SockaddrInet6:
 152                                         if supportsVistaIP {
 153                                                 l = int(puni.OnLinkPrefixLength)
 154                                         } else {
 155                                                 l = addrPrefixLen(pfx6, IP(sa.Addr[:]))
 156                                         }
 157                                         ifa := &IPNet{IP: make(IP, IPv6len), Mask: CIDRMask(l, 8*IPv6len)}
 158                                         copy(ifa.IP, sa.Addr[:])
 159                                         ifat = append(ifat, ifa)
 160                                 }
 161                         }
 162                         for pany := aa.FirstAnycastAddress; pany != nil; pany = pany.Next {
 163                                 sa, err := pany.Address.Sockaddr.Sockaddr()
 164                                 if err != nil {
 165                                         return nil, os.NewSyscallError("sockaddr", err)
 166                                 }
 167                                 switch sa := sa.(type) {
 168                                 case *syscall.SockaddrInet4:
 169                                         ifat = append(ifat, &IPAddr{IP: IPv4(sa.Addr[0], sa.Addr[1], sa.Addr[2], sa.Addr[3])})
 170                                 case *syscall.SockaddrInet6:
 171                                         ifa := &IPAddr{IP: make(IP, IPv6len)}
 172                                         copy(ifa.IP, sa.Addr[:])
 173                                         ifat = append(ifat, ifa)
 174                                 }
 175                         }
 176                 }
 177         }
 178         return ifat, nil
 179 }
 180
 181 func addrPrefixTable(aa *windows.IpAdapterAddresses) (pfx4, pfx6 []IPNet, err error) {
 182         for p := aa.FirstPrefix; p != nil; p = p.Next {
 183                 sa, err := p.Address.Sockaddr.Sockaddr()
 184                 if err != nil {
 185                         return nil, nil, os.NewSyscallError("sockaddr", err)
 186                 }
 187                 switch sa := sa.(type) {
 188                 case *syscall.SockaddrInet4:
 189                         pfx := IPNet{IP: IP(sa.Addr[:]), Mask: CIDRMask(int(p.PrefixLength), 8*IPv4len)}
 190                         pfx4 = append(pfx4, pfx)
 191                 case *syscall.SockaddrInet6:
 192                         pfx := IPNet{IP: IP(sa.Addr[:]), Mask: CIDRMask(int(p.PrefixLength), 8*IPv6len)}
 193                         pfx6 = append(pfx6, pfx)
 194                 }
 195         }
 196         return
 197 }
 198
 199 // addrPrefixLen returns an appropriate prefix length in bits for ip
 200 // from pfxs. It returns 32 or 128 when no appropriate on-link address
 201 // prefix found.
 202 //
 203 // NOTE: This is pretty naive implementation that contains many
 204 // allocations and non-effective linear search, and should not be used
 205 // freely.
 206 func addrPrefixLen(pfxs []IPNet, ip IP) int {
 207         var l int
 208         var cand *IPNet
 209         for i := range pfxs {
 210                 if !pfxs[i].Contains(ip) {
 211                         continue
 212                 }
 213                 if cand == nil {
 214                         l, _ = pfxs[i].Mask.Size()
 215                         cand = &pfxs[i]
 216                         continue
 217                 }
 218                 m, _ := pfxs[i].Mask.Size()
 219                 if m > l {
 220                         l = m
 221                         cand = &pfxs[i]
 222                         continue
 223                 }
 224         }
 225         if l > 0 {
 226                 return l
 227         }
 228         if ip.To4() != nil {
 229                 return 8 * IPv4len
 230         }
 231         return 8 * IPv6len
 232 }
 233
 234 // interfaceMulticastAddrTable returns addresses for a specific
 235 // interface.
 236 func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
 237         aas, err := adapterAddresses()
 238         if err != nil {
 239                 return nil, err
 240         }
 241         var ifat []Addr
 242         for _, aa := range aas {
 243                 index := aa.IfIndex
 244                 if index == 0 { // ipv6IfIndex is a substitute for ifIndex
 245                         index = aa.Ipv6IfIndex
 246                 }
 247                 if ifi == nil || ifi.Index == int(index) {
 248                         for pmul := aa.FirstMulticastAddress; pmul != nil; pmul = pmul.Next {
 249                                 sa, err := pmul.Address.Sockaddr.Sockaddr()
 250                                 if err != nil {
 251                                         return nil, os.NewSyscallError("sockaddr", err)
 252                                 }
 253                                 switch sa := sa.(type) {
 254                                 case *syscall.SockaddrInet4:
 255                                         ifat = append(ifat, &IPAddr{IP: IPv4(sa.Addr[0], sa.Addr[1], sa.Addr[2], sa.Addr[3])})
 256                                 case *syscall.SockaddrInet6:
 257                                         ifa := &IPAddr{IP: make(IP, IPv6len)}
 258                                         copy(ifa.IP, sa.Addr[:])
 259                                         ifat = append(ifat, ifa)
 260                                 }
 261                         }
 262                 }
 263         }
 264         return ifat, nil
 265 }