internal override DnsResourceData CreateInstance(DnsDatagram dns, int offsetInDns, int length) { if (length < ConstantPartLength + DnsDomainName.RootLength) { return(null); } DnsDomainName algorithm; int algorithmLength; if (!DnsDomainName.TryParse(dns, offsetInDns, length - ConstantPartLength, out algorithm, out algorithmLength)) { return(null); } offsetInDns += algorithmLength; length -= algorithmLength; if (length < ConstantPartLength) { return(null); } uint inception = dns.ReadUInt(offsetInDns + OffsetAfterAlgorithm.Inception, Endianity.Big); uint expiration = dns.ReadUInt(offsetInDns + OffsetAfterAlgorithm.Expiration, Endianity.Big); DnsTransactionKeyMode mode = (DnsTransactionKeyMode)dns.ReadUShort(offsetInDns + OffsetAfterAlgorithm.Mode, Endianity.Big); DnsResponseCode error = (DnsResponseCode)dns.ReadUShort(offsetInDns + OffsetAfterAlgorithm.Error, Endianity.Big); int keySize = dns.ReadUShort(offsetInDns + OffsetAfterAlgorithm.KeySize, Endianity.Big); if (length < ConstantPartLength + keySize) { return(null); } DataSegment key = dns.Subsegment(offsetInDns + OffsetAfterAlgorithm.KeyData, keySize); int totalReadAfterAlgorithm = OffsetAfterAlgorithm.KeyData + keySize; offsetInDns += totalReadAfterAlgorithm; length -= totalReadAfterAlgorithm; int otherSize = dns.ReadUShort(offsetInDns, Endianity.Big); if (length != sizeof(ushort) + otherSize) { return(null); } DataSegment other = dns.Subsegment(offsetInDns + sizeof(ushort), otherSize); return(new DnsResourceDataTransactionKey(algorithm, inception, expiration, mode, error, key, other)); }
internal override DnsResourceData CreateInstance(DnsDatagram dns, int offsetInDns, int length) { if (length < ConstantPartLength + DnsDomainName.RootLength) { return(null); } DnsDomainName algorithm; int algorithmLength; if (!DnsDomainName.TryParse(dns, offsetInDns, length - ConstantPartLength, out algorithm, out algorithmLength)) { return(null); } offsetInDns += algorithmLength; length -= algorithmLength; if (length < ConstantPartLength) { return(null); } UInt48 timeSigned = dns.ReadUInt48(offsetInDns + OffsetAfterAlgorithm.TimeSigned, Endianity.Big); ushort fudge = dns.ReadUShort(offsetInDns + OffsetAfterAlgorithm.Fudge, Endianity.Big); int messageAuthenticationCodeLength = dns.ReadUShort(offsetInDns + OffsetAfterAlgorithm.MessageAuthenticationCodeSize, Endianity.Big); if (length < ConstantPartLength + messageAuthenticationCodeLength) { return(null); } DataSegment messageAuthenticationCode = dns.Subsegment(offsetInDns + OffsetAfterAlgorithm.MessageAuthenticationCode, messageAuthenticationCodeLength); int totalReadAfterAlgorithm = OffsetAfterAlgorithm.MessageAuthenticationCode + messageAuthenticationCodeLength; offsetInDns += totalReadAfterAlgorithm; length -= totalReadAfterAlgorithm; ushort originalId = dns.ReadUShort(offsetInDns + OffsetAfterMessageAuthenticationCode.OriginalId, Endianity.Big); DnsResponseCode error = (DnsResponseCode)dns.ReadUShort(offsetInDns + OffsetAfterMessageAuthenticationCode.Error, Endianity.Big); int otherLength = dns.ReadUShort(offsetInDns + OffsetAfterMessageAuthenticationCode.OtherLength, Endianity.Big); if (length != OffsetAfterMessageAuthenticationCode.OtherData + otherLength) { return(null); } DataSegment other = dns.Subsegment(offsetInDns + OffsetAfterMessageAuthenticationCode.OtherData, otherLength); return(new DnsResourceDataTransactionSignature(algorithm, timeSigned, fudge, messageAuthenticationCode, originalId, error, other)); }
internal override DnsResourceData CreateInstance(DnsDatagram dns, int offsetInDns, int length) { if (length < ConstantPartLength) { return(null); } DnsType typeCovered = (DnsType)dns.ReadUShort(offsetInDns + Offset.TypeCovered, Endianity.Big); DnsAlgorithm algorithm = (DnsAlgorithm)dns[offsetInDns + Offset.Algorithm]; byte labels = dns[offsetInDns + Offset.Labels]; uint originalTtl = dns.ReadUInt(offsetInDns + Offset.OriginalTtl, Endianity.Big); uint signatureExpiration = dns.ReadUInt(offsetInDns + Offset.SignatureExpiration, Endianity.Big); uint signatureInception = dns.ReadUInt(offsetInDns + Offset.SignatureInception, Endianity.Big); ushort keyTag = dns.ReadUShort(offsetInDns + Offset.KeyTag, Endianity.Big); offsetInDns += ConstantPartLength; length -= ConstantPartLength; DnsDomainName signersName; int signersNameLength; if (!DnsDomainName.TryParse(dns, offsetInDns, length, out signersName, out signersNameLength)) { return(null); } offsetInDns += signersNameLength; length -= signersNameLength; DataSegment signature = dns.Subsegment(offsetInDns, length); return(new DnsResourceDataSignature(typeCovered, algorithm, labels, originalTtl, signatureExpiration, signatureInception, keyTag, signersName, signature)); }
internal override DnsResourceData CreateInstance(DnsDatagram dns, int offsetInDns, int length) { DnsDomainName nextDomainName; int nextDomainNameLength; if (!DnsDomainName.TryParse(dns, offsetInDns, length, out nextDomainName, out nextDomainNameLength)) { return(null); } offsetInDns += nextDomainNameLength; length -= nextDomainNameLength; if (length > MaxTypeBitmapLength) { return(null); } DataSegment typeBitmap = dns.Subsegment(offsetInDns, length); if (length != 0 && typeBitmap.Last == 0) { return(null); } return(new DnsResourceDataNextDomain(nextDomainName, typeBitmap)); }
internal static DnsResourceData Read(DnsDatagram dns, DnsType type, int offsetInDns, int length) { DnsResourceData prototype = TryGetPrototype(type); if (prototype != null) { return(prototype.CreateInstance(dns, offsetInDns, length)); } return(new DnsResourceDataAnything(dns.Subsegment(offsetInDns, length))); }
internal override DnsResourceData CreateInstance(DnsDatagram dns, int offsetInDns, int length) { if (length < ConstantPartLength) { return(null); } int hostIdentityTagLength = dns[offsetInDns + Offset.HostIdentityTagLength]; DnsPublicKeyAlgorithm publicKeyAlgorithm = (DnsPublicKeyAlgorithm)dns[offsetInDns + Offset.PublicKeyAlgorithm]; int publicKeyLength = dns.ReadUShort(offsetInDns + Offset.PublicKeyLength, Endianity.Big); if (length < ConstantPartLength + hostIdentityTagLength + publicKeyLength) { return(null); } DataSegment hostIdentityTag = dns.Subsegment(offsetInDns + Offset.HostIdentityTag, hostIdentityTagLength); int publicKeyOffset = offsetInDns + ConstantPartLength + hostIdentityTagLength; DataSegment publicKey = dns.Subsegment(publicKeyOffset, publicKeyLength); offsetInDns += ConstantPartLength + hostIdentityTagLength + publicKeyLength; length -= ConstantPartLength + hostIdentityTagLength + publicKeyLength; List <DnsDomainName> rendezvousServers = new List <DnsDomainName>(); while (length != 0) { DnsDomainName rendezvousServer; int rendezvousServerLength; if (!DnsDomainName.TryParse(dns, offsetInDns, length, out rendezvousServer, out rendezvousServerLength)) { return(null); } rendezvousServers.Add(rendezvousServer); offsetInDns += rendezvousServerLength; length -= rendezvousServerLength; } return(new DnsResourceDataHostIdentityProtocol(hostIdentityTag, publicKeyAlgorithm, publicKey, rendezvousServers)); }
internal override DnsResourceData CreateInstance(DnsDatagram dns, int offsetInDns, int length) { if (length < MinimumLength) { return(null); } ushort order = dns.ReadUShort(offsetInDns + Offset.Order, Endianity.Big); ushort preference = dns.ReadUShort(offsetInDns + Offset.Preference, Endianity.Big); DataSegment data = dns.Subsegment(offsetInDns + ConstantPartLength, length - ConstantPartLength); int dataOffset = 0; DataSegment flags = ReadString(data, ref dataOffset); if (flags == null || !IsLegalFlags(flags)) { return(null); } DataSegment services = ReadString(data, ref dataOffset); if (services == null) { return(null); } DataSegment regexp = ReadString(data, ref dataOffset); if (regexp == null) { return(null); } DnsDomainName replacement; int replacementLength; if (!DnsDomainName.TryParse(dns, offsetInDns + ConstantPartLength + dataOffset, length - ConstantPartLength - dataOffset, out replacement, out replacementLength)) { return(null); } if (ConstantPartLength + dataOffset + replacementLength != length) { return(null); } return(new DnsResourceDataNamingAuthorityPointer(order, preference, flags, services, regexp, replacement)); }
private static bool TryReadLabels(DnsDatagram dns, int offsetInDns, out int numBytesRead, List <DataSegment> labels) { numBytesRead = 0; byte labelLength; do { if (offsetInDns >= dns.Length) { return(false); // Can't read label's length. } labelLength = dns[offsetInDns]; ++numBytesRead; if (labelLength > MaxLabelLength) { // Compression. if (offsetInDns + 1 >= dns.Length) { return(false); // Can't read compression pointer. } int newOffsetInDns = dns.ReadUShort(offsetInDns, Endianity.Big) & OffsetMask; if (newOffsetInDns >= offsetInDns) { return(false); // Can't handle pointers that are not back pointers. } ++numBytesRead; int internalBytesRead; return(TryReadLabels(dns, newOffsetInDns, out internalBytesRead, labels)); } if (labelLength != 0) { ++offsetInDns; if (offsetInDns + labelLength >= dns.Length) { return(false); // Can't read label. } labels.Add(dns.Subsegment(offsetInDns, labelLength)); numBytesRead += labelLength; offsetInDns += labelLength; } } while (labelLength != 0); return(true); }
internal override DnsResourceData CreateInstance(DnsDatagram dns, int offsetInDns, int length) { if (length < ConstPartLength) { return(null); } byte precedence = dns[offsetInDns + Offset.Precedence]; DnsGatewayType gatewayType = (DnsGatewayType)dns[offsetInDns + Offset.GatewayType]; DnsPublicKeyAlgorithm algorithm = (DnsPublicKeyAlgorithm)dns[offsetInDns + Offset.Algorithm]; DnsGateway gateway = DnsGateway.CreateInstance(gatewayType, dns, offsetInDns + Offset.Gateway, length - ConstPartLength); if (gateway == null) { return(null); } DataSegment publicKey = dns.Subsegment(offsetInDns + ConstPartLength + gateway.Length, length - ConstPartLength - gateway.Length); return(new DnsResourceDataIpSecKey(precedence, gateway, algorithm, publicKey)); }