123 lines
3.3 KiB
Go
123 lines
3.3 KiB
Go
package config
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import (
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"net"
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"os"
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"syscall"
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"unsafe"
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"golang.org/x/sys/windows"
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)
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const GAA_FLAG_INCLUDE_GATEWAYS = 0x00000080
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type IpAdapterWinsServerAddress struct {
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Length uint32
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_ uint32
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Next *IpAdapterWinsServerAddress
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Address windows.SocketAddress
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}
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type IpAdapterGatewayAddress struct {
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Length uint32
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_ uint32
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Next *IpAdapterGatewayAddress
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Address windows.SocketAddress
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}
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type IpAdapterAddresses struct {
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Length uint32
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IfIndex uint32
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Next *IpAdapterAddresses
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AdapterName *byte
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FirstUnicastAddress *windows.IpAdapterUnicastAddress
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FirstAnycastAddress *windows.IpAdapterAnycastAddress
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FirstMulticastAddress *windows.IpAdapterMulticastAddress
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FirstDnsServerAddress *windows.IpAdapterDnsServerAdapter
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DnsSuffix *uint16
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Description *uint16
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FriendlyName *uint16
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PhysicalAddress [syscall.MAX_ADAPTER_ADDRESS_LENGTH]byte
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PhysicalAddressLength uint32
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Flags uint32
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Mtu uint32
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IfType uint32
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OperStatus uint32
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Ipv6IfIndex uint32
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ZoneIndices [16]uint32
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FirstPrefix *windows.IpAdapterPrefix
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/* more fields might be present here. */
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TransmitLinkSpeed uint64
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ReceiveLinkSpeed uint64
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FirstWINSServerAddress *IpAdapterWinsServerAddress
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FirstGatewayAddress *IpAdapterGatewayAddress
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}
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func adapterAddresses() ([]*IpAdapterAddresses, error) {
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var b []byte
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// https://docs.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-getadaptersaddresses
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// #define WORKING_BUFFER_SIZE 15000
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l := uint32(15000)
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for {
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b = make([]byte, l)
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err := windows.GetAdaptersAddresses(syscall.AF_UNSPEC, GAA_FLAG_INCLUDE_GATEWAYS|windows.GAA_FLAG_INCLUDE_PREFIX, 0, (*windows.IpAdapterAddresses)(unsafe.Pointer(&b[0])), &l)
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if err == nil {
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if l == 0 {
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return nil, nil
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}
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break
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}
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if err.(syscall.Errno) != syscall.ERROR_BUFFER_OVERFLOW {
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return nil, os.NewSyscallError("getadaptersaddresses", err)
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}
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if l <= uint32(len(b)) {
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return nil, os.NewSyscallError("getadaptersaddresses", err)
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}
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}
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aas := make([]*IpAdapterAddresses, 0, uintptr(l)/unsafe.Sizeof(IpAdapterAddresses{}))
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for aa := (*IpAdapterAddresses)(unsafe.Pointer(&b[0])); aa != nil; aa = aa.Next {
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aas = append(aas, aa)
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}
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return aas, nil
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}
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/// As per [RFC 3879], the whole `FEC0::/10` prefix is
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/// deprecated. New software must not support site-local
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/// addresses.
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///
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/// [RFC 3879]: https://tools.ietf.org/html/rfc3879
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func isUnicastLinkLocal(ip net.IP) bool {
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return len(ip) == net.IPv6len && ip[0] == 0xfe && ip[1] == 0xc0
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}
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func GetDefaultDnsServers() ([]string, error) {
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ifs, err := adapterAddresses()
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if err != nil {
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return nil, err
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}
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dnsServers := make([]string, 0)
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for _, ifi := range ifs {
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if ifi.OperStatus != windows.IfOperStatusUp {
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continue
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}
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if ifi.FirstGatewayAddress == nil {
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continue
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}
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for dnsServer := ifi.FirstDnsServerAddress; dnsServer != nil; dnsServer = dnsServer.Next {
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ip := dnsServer.Address.IP()
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if isUnicastLinkLocal(ip) {
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continue
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}
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dnsServers = append(dnsServers, ip.String())
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}
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}
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return dnsServers, nil
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}
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func GetDefaultServers() ([]string, int, []string, error) {
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// TODO: DNS Suffix
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servers, err := GetDefaultDnsServers()
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return servers, 0, nil, err
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}
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