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feature: Bootstrapper secure server discovery

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This commit is contained in:
Gary Sharp
2026-01-22 15:26:23 +11:00
parent 71fa53bfb2
commit e1f1973520
40 changed files with 2094 additions and 460 deletions
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Disco.Services/Interop/DNS/NativeDns.cs
+202
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using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Threading;
namespace Disco.Services.Interop.DNS
{
internal static class NativeDns
{
[DllImport("dnsapi", EntryPoint = "DnsQuery_W", CharSet = CharSet.Unicode, SetLastError = true, ExactSpelling = true)]
private static extern int DnsQuery([MarshalAs(UnmanagedType.VBByRefStr)] ref string pszName, NativeDnsQueryTypes wType, NativeDnsQueryOptions options, int aipServers, ref IntPtr ppQueryResults, int pReserved);
[DllImport("dnsapi", CharSet = CharSet.Auto, SetLastError = true)]
private static extern void DnsRecordListFree(IntPtr pRecordList, int FreeType);
private const int DNS_ERROR_RCODE_NAME_ERROR = 0x232B;
private const int DNS_ERROR_BAD_PACKET = 0x251E;
public static List<DnsRecord> QueryRecords(DnsRecordType type, string name, bool bypassCache)
{
NativeDnsQueryTypes queryType;
Func<IntPtr, Tuple<DnsRecord, IntPtr>> marshaller;
switch (type)
{
case DnsRecordType.A:
queryType = NativeDnsQueryTypes.DNS_TYPE_A;
marshaller = MarshalARecord;
break;
case DnsRecordType.Cname:
queryType = NativeDnsQueryTypes.DNS_TYPE_CNAME;
marshaller = MarshalCnameRecord;
break;
case DnsRecordType.Txt:
queryType = NativeDnsQueryTypes.DNS_TYPE_TEXT;
marshaller = MarshalTxtRecord;
break;
case DnsRecordType.Srv:
queryType = NativeDnsQueryTypes.DNS_TYPE_SRV;
marshaller = MarshalSrvRecord;
break;
default:
throw new NotSupportedException($"Unsupported DNS record type: {type}");
}
IntPtr rrPointers = IntPtr.Zero;
var records = new List<DnsRecord>();
var retry = 5;
retry:
try
{
int queryResult = DnsQuery(ref name, queryType, bypassCache ? NativeDnsQueryOptions.DNS_QUERY_BYPASS_CACHE : NativeDnsQueryOptions.DNS_QUERY_STANDARD, 0, ref rrPointers, 0);
if (queryResult != 0)
{
if (queryResult == DNS_ERROR_RCODE_NAME_ERROR)
return records;
else if (queryResult == DNS_ERROR_BAD_PACKET && retry > 0)
{
// Sometimes a BAD_PACKET error is returned, retry a few times
Thread.Sleep(100);
retry--;
goto retry;
}
else
throw new Win32Exception(queryResult);
}
for (var rrPointer = rrPointers; !rrPointer.Equals(IntPtr.Zero);)
{
var (record, rrPointerNext) = marshaller(rrPointer);
records.Add(record);
rrPointer = rrPointerNext;
}
}
finally
{
if (rrPointers != IntPtr.Zero)
DnsRecordListFree(rrPointers, 0);
}
return records;
}
private static Tuple<DnsRecord, IntPtr> MarshalARecord(IntPtr pointer)
{
var native = Marshal.PtrToStructure<NativeDnsAData>(pointer);
var record = new ADnsRecord(native.pName, TimeSpan.FromSeconds(native.dwTtl), native.IpAddress);
return Tuple.Create((DnsRecord)record, native.pNext);
}
private static Tuple<DnsRecord, IntPtr> MarshalCnameRecord(IntPtr pointer)
{
var native = Marshal.PtrToStructure<NativeDnsPtrData>(pointer);
var record = new CnameDnsRecord(native.pName, TimeSpan.FromSeconds(native.dwTtl), native.pNameHost);
return Tuple.Create((DnsRecord)record, native.pNext);
}
private static Tuple<DnsRecord, IntPtr> MarshalTxtRecord(IntPtr pointer)
{
var native = Marshal.PtrToStructure<NativeDnsTxtData>(pointer);
var record = new TxtDnsRecord(native.pName, TimeSpan.FromSeconds(native.dwTtl), native.pStringArray);
return Tuple.Create((DnsRecord)record, native.pNext);
}
private static Tuple<DnsRecord, IntPtr> MarshalSrvRecord(IntPtr pointer)
{
var native = Marshal.PtrToStructure<NativeDnsSrvData>(pointer);
var record = new SrvDnsRecord(native.pName, TimeSpan.FromSeconds(native.dwTtl), native.pNameTarget, native.wPriority, native.wWeight, native.wPort);
return Tuple.Create((DnsRecord)record, native.pNext);
}
private enum NativeDnsQueryOptions
{
DNS_QUERY_ACCEPT_TRUNCATED_RESPONSE = 1,
DNS_QUERY_BYPASS_CACHE = 8,
DNS_QUERY_DONT_RESET_TTL_VALUES = 0x100000,
DNS_QUERY_NO_HOSTS_FILE = 0x40,
DNS_QUERY_NO_LOCAL_NAME = 0x20,
DNS_QUERY_NO_NETBT = 0x80,
DNS_QUERY_NO_RECURSION = 4,
DNS_QUERY_NO_WIRE_QUERY = 0x10,
DNS_QUERY_RESERVED = -16777216,
DNS_QUERY_RETURN_MESSAGE = 0x200,
DNS_QUERY_STANDARD = 0,
DNS_QUERY_TREAT_AS_FQDN = 0x1000,
DNS_QUERY_USE_TCP_ONLY = 2,
DNS_QUERY_WIRE_ONLY = 0x100
}
private enum NativeDnsQueryTypes
{
DNS_TYPE_A = 0x0001,
DNS_TYPE_CNAME = 0x0005,
DNS_TYPE_TEXT = 0x0010,
DNS_TYPE_SRV = 0x0021
}
[StructLayout(LayoutKind.Sequential)]
private struct NativeDnsSrvData
{
public IntPtr pNext;
[MarshalAs(UnmanagedType.LPWStr)]
public string pName;
public ushort wType;
public ushort wDataLength;
public int flags;
public int dwTtl;
public int dwReserved;
[MarshalAs(UnmanagedType.LPWStr)]
public string pNameTarget;
public ushort wPriority;
public ushort wWeight;
public ushort wPort;
public ushort Pad;
}
[StructLayout(LayoutKind.Sequential)]
private struct NativeDnsTxtData
{
public IntPtr pNext;
[MarshalAs(UnmanagedType.LPWStr)]
public string pName;
public ushort wType;
public ushort wDataLength;
public int flags;
public int dwTtl;
public int dwReserved;
public uint dwStringLength;
[MarshalAs(UnmanagedType.LPWStr)]
public string pStringArray;
}
[StructLayout(LayoutKind.Sequential)]
private struct NativeDnsPtrData
{
public IntPtr pNext;
[MarshalAs(UnmanagedType.LPWStr)]
public string pName;
public ushort wType;
public ushort wDataLength;
public int flags;
public int dwTtl;
public int dwReserved;
[MarshalAs(UnmanagedType.LPWStr)]
public string pNameHost;
}
[StructLayout(LayoutKind.Sequential)]
private struct NativeDnsAData
{
public IntPtr pNext;
[MarshalAs(UnmanagedType.LPWStr)]
public string pName;
public ushort wType;
public ushort wDataLength;
public int flags;
public int dwTtl;
public int dwReserved;
public uint IpAddress;
}
}
}