/// <summary>
/// Create the security option from the different security field values.
/// </summary>
/// <param name="classificationLevel">
/// This field specifies the (U.S.) classification level at which the datagram must be protected.
/// The information in the datagram must be protected at this level.
/// </param>
/// <param name="protectionAuthorities">
/// This field identifies the National Access Programs or Special Access Programs
/// which specify protection rules for transmission and processing of the information contained in the datagram.
/// </param>
/// <param name="length">
/// The number of bytes this option will take.
/// </param>
public IpV4OptionBasicSecurity(IpV4OptionSecurityClassificationLevel classificationLevel, IpV4OptionSecurityProtectionAuthorities protectionAuthorities, byte length)
: base(IpV4OptionType.BasicSecurity)
{
if (length < OptionMinimumLength)
{
throw new ArgumentOutOfRangeException("length", length, "Minimum option length is " + OptionMinimumLength);
}
if (length == OptionMinimumLength && protectionAuthorities != IpV4OptionSecurityProtectionAuthorities.None)
{
throw new ArgumentException("Can't have a protection authority without minimum of " + (OptionValueMinimumLength + 1) + " length",
"protectionAuthorities");
}
if (classificationLevel != IpV4OptionSecurityClassificationLevel.Confidential &&
classificationLevel != IpV4OptionSecurityClassificationLevel.Secret &&
classificationLevel != IpV4OptionSecurityClassificationLevel.TopSecret &&
classificationLevel != IpV4OptionSecurityClassificationLevel.Unclassified)
{
throw new ArgumentException("Invalid classification level " + classificationLevel);
}
_classificationLevel = classificationLevel;
_protectionAuthorities = protectionAuthorities;
_length = length;
}
/// <summary>
/// Tries to read the option from a buffer starting from the option value (after the type and length).
/// </summary>
/// <param name="buffer">The buffer to read the option from.</param>
/// <param name="offset">The offset to the first byte to read the buffer. Will be incremented by the number of bytes read.</param>
/// <param name="valueLength">The number of bytes the option value should take according to the length field that was already read.</param>
/// <returns>On success - the complex option read. On failure - null.</returns>
Option IOptionComplexFactory.CreateInstance(byte[] buffer, ref int offset, byte valueLength)
{
// if (buffer == null)
// throw new ArgumentNullException("buffer");
if (valueLength < OptionValueMinimumLength)
{
return(null);
}
// Classification level
IpV4OptionSecurityClassificationLevel classificationLevel = (IpV4OptionSecurityClassificationLevel)buffer[offset++];
if (classificationLevel != IpV4OptionSecurityClassificationLevel.Confidential &&
classificationLevel != IpV4OptionSecurityClassificationLevel.Secret &&
classificationLevel != IpV4OptionSecurityClassificationLevel.TopSecret &&
classificationLevel != IpV4OptionSecurityClassificationLevel.Unclassified)
{
return(null);
}
// Protection authorities
int protectionAuthoritiesLength = valueLength - OptionValueMinimumLength;
IpV4OptionSecurityProtectionAuthorities protectionAuthorities = IpV4OptionSecurityProtectionAuthorities.None;
if (protectionAuthoritiesLength > 0)
{
for (int i = 0; i < protectionAuthoritiesLength - 1; ++i)
{
if ((buffer[offset + i] & 0x01) == 0)
{
return(null);
}
}
if ((buffer[offset + protectionAuthoritiesLength - 1] & 0x01) != 0)
{
return(null);
}
protectionAuthorities = (IpV4OptionSecurityProtectionAuthorities)(buffer[offset] & 0xFE);
}
offset += protectionAuthoritiesLength;
return(new IpV4OptionBasicSecurity(classificationLevel, protectionAuthorities, (byte)(OptionMinimumLength + protectionAuthoritiesLength)));
}
public IpV4OptionBasicSecurity(IpV4OptionSecurityClassificationLevel classificationLevel, IpV4OptionSecurityProtectionAuthorities protectionAuthorities, byte length)
: base(IpV4OptionType.BasicSecurity)
{
if ((int)length < 3)
{
throw new ArgumentOutOfRangeException("length", (object)length, "Minimum option length is " + (object)3);
}
if ((int)length == 3 && protectionAuthorities != IpV4OptionSecurityProtectionAuthorities.None)
{
throw new ArgumentException("Can't have a protection authority without minimum of " + (object)2 + " length", "protectionAuthorities");
}
if (classificationLevel != IpV4OptionSecurityClassificationLevel.Confidential && classificationLevel != IpV4OptionSecurityClassificationLevel.Secret && (classificationLevel != IpV4OptionSecurityClassificationLevel.TopSecret && classificationLevel != IpV4OptionSecurityClassificationLevel.Unclassified))
{
throw new ArgumentException("Invalid classification level " + (object)classificationLevel);
}
this._classificationLevel = classificationLevel;
this._protectionAuthorities = protectionAuthorities;
this._length = length;
}
Option IOptionComplexFactory.CreateInstance(byte[] buffer, ref int offset, byte valueLength)
{
if ((int)valueLength < 1)
{
return((Option)null);
}
IpV4OptionSecurityClassificationLevel classificationLevel = (IpV4OptionSecurityClassificationLevel)buffer[offset++];
switch (classificationLevel)
{
case IpV4OptionSecurityClassificationLevel.Confidential:
case IpV4OptionSecurityClassificationLevel.Secret:
case IpV4OptionSecurityClassificationLevel.TopSecret:
case IpV4OptionSecurityClassificationLevel.Unclassified:
int num = (int)valueLength - 1;
IpV4OptionSecurityProtectionAuthorities protectionAuthorities = IpV4OptionSecurityProtectionAuthorities.None;
if (num > 0)
{
for (int index = 0; index < num - 1; ++index)
{
if (((int)buffer[offset + index] & 1) == 0)
{
return((Option)null);
}
}
if (((int)buffer[offset + num - 1] & 1) != 0)
{
return((Option)null);
}
protectionAuthorities = (IpV4OptionSecurityProtectionAuthorities)((uint)buffer[offset] & 254U);
}
offset += num;
return((Option) new IpV4OptionBasicSecurity(classificationLevel, protectionAuthorities, (byte)(3 + num)));
default:
return((Option)null);
}
}
/// <summary>
/// Create the security option with only classification level.
/// </summary>
/// <param name="classificationLevel">
/// This field specifies the (U.S.) classification level at which the datagram must be protected.
/// The information in the datagram must be protected at this level.
/// </param>
public IpV4OptionBasicSecurity(IpV4OptionSecurityClassificationLevel classificationLevel)
: this(classificationLevel, IpV4OptionSecurityProtectionAuthorities.None, OptionMinimumLength)
{
}
public IpV4OptionBasicSecurity(IpV4OptionSecurityClassificationLevel classificationLevel)
: this(classificationLevel, IpV4OptionSecurityProtectionAuthorities.None, (byte)3)
{
}
