/// <summary>
/// Constructs an instance out of the key tag, algorithm, digest type and digest fields.
/// </summary>
/// <param name="keyTag">
/// Lists the key tag of the DNSKEY RR referred to by the DS record.
/// The Key Tag used by the DS RR is identical to the Key Tag used by RRSIG RRs.
/// Calculated as specified in RFC 2535.
/// </param>
/// <param name="algorithm">Algorithm must be allowed to sign DNS data.</param>
/// <param name="digestType">An identifier for the digest algorithm used.</param>
/// <param name="digest">
/// Calculated over the canonical name of the delegated domain name followed by the whole RDATA of the KEY record (all four fields).
/// digest = hash(canonical FQDN on KEY RR | KEY_RR_rdata)
/// KEY_RR_rdata = Flags | Protocol | Algorithm | Public Key
/// The size of the digest may vary depending on the digest type.
/// </param>
public DnsResourceDataDelegationSigner(ushort keyTag, DnsAlgorithm algorithm, DnsDigestType digestType, DataSegment digest)
{
if (digest == null)
{
throw new ArgumentNullException("digest");
}
KeyTag = keyTag;
Algorithm = algorithm;
DigestType = digestType;
int maxDigestLength;
switch (DigestType)
{
case DnsDigestType.Sha1:
maxDigestLength = 20;
break;
case DnsDigestType.Sha256:
maxDigestLength = 32;
break;
default:
maxDigestLength = int.MaxValue;
break;
}
Digest = digest.Subsegment(0, Math.Min(digest.Length, maxDigestLength));
ExtraDigest = digest.Subsegment(Digest.Length, digest.Length - Digest.Length);
}
internal override DnsResourceData CreateInstance(DataSegment data)
{
ushort keyTag = data.ReadUShort(Offset.KeyTag, Endianity.Big);
DnsAlgorithm algorithm = (DnsAlgorithm)data[Offset.Algorithm];
DnsDigestType digestType = (DnsDigestType)data[Offset.DigestType];
DataSegment digest = data.Subsegment(Offset.Digest, data.Length - ConstPartLength);
return(new DnsResourceDataDelegationSigner(keyTag, algorithm, digestType, digest));
}
public DnsResourceDataDelegationSigner(ushort keyTag, DnsAlgorithm algorithm, DnsDigestType digestType, DataSegment digest)
{
if (digest == null)
{
throw new ArgumentNullException("digest");
}
this.KeyTag = keyTag;
this.Algorithm = algorithm;
this.DigestType = digestType;
int val2;
switch (this.DigestType)
{
case DnsDigestType.Sha1:
val2 = 20;
break;
case DnsDigestType.Sha256:
val2 = 32;
break;
default:
val2 = int.MaxValue;
break;
}
this.Digest = digest.Subsegment(0, Math.Min(digest.Length, val2));
this.ExtraDigest = digest.Subsegment(this.Digest.Length, digest.Length - this.Digest.Length);
}