dotnet-core_mail-server/SMTPServer/DNSResolver/DnsHelper.cs

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C#
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2016-11-23 21:32:40 +00:00
using System;
using System.Text;
namespace DNSResolver
{
internal static class DnsHelpers
{
private const long Epoch = 621355968000000000;
internal static byte[] CanonicaliseDnsName(string name, bool lowerCase)
{
if (!name.EndsWith("."))
{
name += ".";
}
if (name == ".")
{
return new byte[1];
}
StringBuilder sb = new StringBuilder();
sb.Append('\0');
for (int i = 0, j = 0; i < name.Length; i++, j++)
{
if (lowerCase)
{
sb.Append(char.ToLower(name[i]));
}
else
{
sb.Append(name[i]);
}
if (name[i] == '.')
{
sb[i - j] = (char)(j & 0xff);
j = -1;
}
}
sb[sb.Length - 1] = '\0';
return Encoding.ASCII.GetBytes(sb.ToString());
}
internal static String DumpArrayToString(byte[] bytes)
{
StringBuilder builder = new StringBuilder();
builder.Append("[");
foreach (byte b in bytes)
{
builder.Append(" ");
builder.Append((sbyte)b);
builder.Append(" ");
}
builder.Append("]");
return builder.ToString();
}
/// <summary>
/// Converts a instance of a <see cref="DateTime"/> class to a 48 bit format time since epoch.
/// Epoch is defined as 1-Jan-70 UTC.
/// </summary>
/// <param name="dateTimeToConvert">The <see cref="DateTime"/> instance to convert to DNS format.</param>
/// <param name="timeHigh">The upper 16 bits of time.</param>
/// <param name="timeLow">The lower 32 bits of the time object.</param>
internal static void ConvertToDnsTime(DateTime dateTimeToConvert, out int timeHigh, out long timeLow)
{
long secondsFromEpoch = (dateTimeToConvert.ToUniversalTime().Ticks - Epoch) / 10000000;
timeHigh = (int)(secondsFromEpoch >> 32);
timeLow = (secondsFromEpoch & 0xFFFFFFFFL);
Logging.AddLogMessage(LoggingType.TRACE, "test");
Trace.WriteLine(String.Format("Date: {0}", dateTimeToConvert));
Trace.WriteLine(String.Format("secondsFromEpoch: {0}", secondsFromEpoch));
Trace.WriteLine(String.Format("timeHigh: {0}", timeHigh));
Trace.WriteLine(String.Format("timeLow: {0}", timeLow));
}
/// <summary>
/// Convert from DNS 48 but time format to a <see cref="DateTime"/> instance.
/// </summary>
/// <param name="timeHigh">The upper 16 bits of time.</param>
/// <param name="timeLow">The lower 32 bits of the time object.</param>
/// <returns>The converted date time</returns>
internal static DateTime ConvertFromDnsTime(long timeLow, long timeHigh)
{
long time = (timeHigh << 32) + timeLow;
time = time * 10000000;
time += Epoch;
return new DateTime(time);
}
/// <summary>
/// Convert from DNS 48 but time format to a <see cref="DateTime"/> instance.
/// </summary>
/// <param name="dnsTime">The upper 48 bits of time.</param>
/// <returns>The converted date time</returns>
internal static DateTime ConvertFromDnsTime(long dnsTime)
{
dnsTime = dnsTime * 10000000;
dnsTime += Epoch;
return new DateTime(dnsTime);
}
}
}