/// <summary>
/// Creates a new instance of <see cref="NbName"/>
/// </summary>
/// <param name="netbiosName">Unencoded Netbios Name label</param>
/// <param name="netbiosSuffix">Netbios Suffix</param>
/// <param name="netbiosScope">Netbios Scope</param>
/// <remarks>
/// We only perform length checks of <see cref="netbiosName"/> and <see cref="netbiosScope"/>
/// The caller must make sure that the characters in these parameters can be converted into a
/// single byte via ISO-8859-1 encoding. If this is not the case, an exception will be thrown later
/// when the <see cref="NbName"/> is encoded into a byte array.
/// </remarks>
public NbName(string netbiosName, KnownNetbiosSuffixes netbiosSuffix, string netbiosScope = null)
{
// Validity checks for netbiosName
if (netbiosName == null)
{
throw new ArgumentNullException("netbiosName");
}
if (netbiosName.Length > MAX_NAME_LENGTH_CLEARTEXT || netbiosName.Length < 1)
{
throw new ArgumentException("netbiosName");
}
_netbiosName = netbiosName;
_netbiosSuffix = netbiosSuffix;
// Validity checks for netbiosScope
if (String.IsNullOrEmpty(netbiosScope))
{
_netbiosScope = null;
return;
}
var scopeLabels = netbiosScope.Split(SCOPE_SEPARATOR);
if (scopeLabels.Any(label => label.Length > MAX_LABEL_LENGTH))
{
throw new ArgumentException("netbiosScope");
}
_netbiosScope = netbiosScope;
// Max length check for the whole NbName
if (GetLength() > MAX_DOMAIN_NAME_LENGHT)
{
throw new ArgumentException("netbiosScope");
}
}
/// <summary>
/// Tries to parse a <see cref="NbName"/> from a buffer of bytes
/// </summary>
/// <param name="buffer">Byte array containing the NbName</param>
/// <param name="offset">Zero based offset in the buffer where the NbName starts</param>
/// <param name="nbName">Parsed NbName if successful, else null</param>
/// <returns><c>true</c> if parsing was successful, else <c>false</c></returns>
public static bool TryParse(byte[] buffer, int offset, out NbName nbName)
{
nbName = null;
if (buffer == null)
{
return(false);
}
if (offset < 0 || offset >= buffer.Length)
{
return(false);
}
if (buffer[offset] == 0x00)
{
return(false);
}
string name = null;
KnownNetbiosSuffixes suffix = 0;
string scope = null;
while (buffer[offset] != 0x00)
{
// If the current byte is a label string pointer (the first two bits are set)
if (buffer[offset] >= 192)
{
// Then the fourteen bits starting at bit three of the current byte represent a pointer to the label in the buffer
if (offset + 1 >= buffer.Length)
{
return(false);
}
var pointer = BitConverter.ToUInt16(buffer, offset);
pointer &= Convert.ToUInt16("0011111111111111", 2);
if (pointer >= buffer.Length)
{
return(false);
}
offset = pointer;
}
// If the current byte is not a laber string pointer (the first two bits are not set)
else if (buffer[offset] < 64)
{
// Then the current byte represents the length of the label
var length = buffer[offset];
offset++;
if (length % 2 != 0 || offset + length >= buffer.Length)
{
return(false);
}
if (name == null)
{
// label must be the netbiosName label
var nameAndSuffix = LevelOneDecode(buffer, offset, length);
suffix = (KnownNetbiosSuffixes)nameAndSuffix[nameAndSuffix.Length - 1];
name = nameAndSuffix.Substring(0, nameAndSuffix.Length - 1);
// Wildcard names are padded with null bytes, other names are padded with spaces
name = name.Trim('\0', ' ');
}
else
{
// label must be a scope label
scope = (scope == null) ? ENCODING.GetString(buffer, offset, length) : scope + "." + ENCODING.GetString(buffer, offset, length);
}
offset += length;
}
else
{
return(false);
}
}
nbName = new NbName(name, suffix, scope);
return(true);
}
