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) { if (length < ConstantPartLength) { return(null); } ushort priortiy = dns.ReadUShort(offsetInDns + Offset.Priority, Endianity.Big); ushort weight = dns.ReadUShort(offsetInDns + Offset.Weight, Endianity.Big); ushort port = dns.ReadUShort(offsetInDns + Offset.Port, Endianity.Big); DnsDomainName target; int targetLength; if (!DnsDomainName.TryParse(dns, offsetInDns + Offset.Target, length - ConstantPartLength, out target, out targetLength)) { return(null); } if (ConstantPartLength + targetLength != length) { return(null); } return(new DnsResourceDataServerSelection(priortiy, weight, port, target)); }
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)); }
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 static bool TryRead(out ushort value, out DnsDomainName domainName, DnsDatagram dns, int offsetInDns, int length) { if (length < ConstantPartLength) { value = 0; domainName = null; return(false); } value = dns.ReadUShort(offsetInDns + Offset.Value, Endianity.Big); length -= ConstantPartLength; int domainNameLength; if (!DnsDomainName.TryParse(dns, offsetInDns + Offset.DomainName, length, out domainName, out domainNameLength)) { return(false); } length -= domainNameLength; if (length != 0) { return(false); } return(true); }
internal static bool TryParseBase(DnsDatagram dns, int offsetInDns, out DnsDomainName domainName, out DnsType type, out DnsClass dnsClass, out int numBytesRead) { type = DnsType.Any; dnsClass = DnsClass.Any; if (!DnsDomainName.TryParse(dns, offsetInDns, dns.Length - offsetInDns, out domainName, out numBytesRead)) { return(false); } if (offsetInDns + numBytesRead + MinimumLengthAfterDomainName > dns.Length) { return(false); } type = (DnsType)dns.ReadUShort(offsetInDns + numBytesRead + OffsetAfterDomainName.Type, Endianity.Big); dnsClass = (DnsClass)dns.ReadUShort(offsetInDns + numBytesRead + OffsetAfterDomainName.DnsClass, Endianity.Big); numBytesRead += MinimumLengthAfterDomainName; return(true); }
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 < 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 static DnsDataResourceRecord Parse(DnsDatagram dns, int offsetInDns, out int numBytesRead) { DnsDomainName domainName; DnsType type; DnsClass dnsClass; if (!TryParseBase(dns, offsetInDns, out domainName, out type, out dnsClass, out numBytesRead)) { return(null); } if (offsetInDns + numBytesRead + MinimumLengthAfterBase > dns.Length) { return(null); } int ttl = dns.ReadInt(offsetInDns + numBytesRead + OffsetAfterBase.Ttl, Endianity.Big); ushort dataLength = dns.ReadUShort(offsetInDns + numBytesRead + OffsetAfterBase.DataLength, Endianity.Big); numBytesRead += MinimumLengthAfterBase; if (offsetInDns + numBytesRead + dataLength > dns.Length) { return(null); } DnsResourceData data = DnsResourceData.Read(dns, type, offsetInDns + numBytesRead, dataLength); if (data == null) { return(null); } numBytesRead += dataLength; if (type == DnsType.Opt) { return(new DnsOptResourceRecord(domainName, dnsClass, ttl, data)); } return(new DnsDataResourceRecord(domainName, type, dnsClass, ttl, data)); }
internal override DnsResourceData CreateInstance(DnsDatagram dns, int offsetInDns, int length) { if (length < ConstantPartLength) { return(null); } ushort preference = dns.ReadUShort(offsetInDns + Offset.Preference, Endianity.Big); offsetInDns += ConstantPartLength; length -= ConstantPartLength; DnsDomainName map822; int map822Length; if (!DnsDomainName.TryParse(dns, offsetInDns, length, out map822, out map822Length)) { return(null); } offsetInDns += map822Length; length -= map822Length; DnsDomainName mapX400; int mapX400Length; if (!DnsDomainName.TryParse(dns, offsetInDns, length, out mapX400, out mapX400Length)) { return(null); } length -= mapX400Length; if (length != 0) { return(null); } return(new DnsResourceDataX400Pointer(preference, map822, mapX400)); }