internal override DnsResourceData CreateInstance(DnsDatagram dns, int offsetInDns, int length) { if (length < MinimumLength) { return(null); } byte prefixLength = dns[offsetInDns + Offset.PrefixLength]; if (prefixLength > MaxPrefixLength) { return(null); } offsetInDns += ConstantPartLength; length -= ConstantPartLength; int addressSuffixLength = CalculateAddressSuffixLength(prefixLength); if (length < addressSuffixLength) { return(null); } IpV6Address addressSuffix = new IpV6Address((UInt128)dns.ReadUnsignedBigInteger(offsetInDns, addressSuffixLength, Endianity.Big)); offsetInDns += addressSuffixLength; length -= addressSuffixLength; if (IsAddressSuffixTooSmall(prefixLength, addressSuffix) || IsAddressSuffixTooBig(prefixLength, addressSuffix)) { return(null); } DnsDomainName prefixName; int prefixNameLength; if (!DnsDomainName.TryParse(dns, offsetInDns, length, out prefixName, out prefixNameLength)) { return(null); } if (prefixNameLength != length) { return(null); } return(new DnsResourceDataA6(prefixLength, addressSuffix, prefixName)); }
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) { int numBytesRead; DnsDomainName domainName; if (!DnsDomainName.TryParse(dns, offsetInDns, length, out domainName, out numBytesRead)) { return(null); } length -= numBytesRead; if (length != 0) { return(null); } return(new DnsResourceDataDomainName(domainName)); }
internal static List <DnsDomainName> ReadDomainNames(DnsDatagram dns, int offsetInDns, int length, int numExpected = 0) { List <DnsDomainName> domainNames = new List <DnsDomainName>(numExpected); while (length != 0) { DnsDomainName domainName; int domainNameLength; if (!DnsDomainName.TryParse(dns, offsetInDns, length, out domainName, out domainNameLength)) { return(null); } offsetInDns += domainNameLength; length -= domainNameLength; domainNames.Add(domainName); } return(domainNames); }
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); }
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)); }
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; DnsTypeBitmaps typeBitmaps = DnsTypeBitmaps.CreateInstance(dns.Buffer, dns.StartOffset + offsetInDns, length); if (typeBitmaps == null) { return(null); } return(new DnsResourceDataNextDomainSecure(nextDomainName, typeBitmaps)); }
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)); }
internal abstract DnsResourceData CreateInstance(DnsDatagram dns, int offsetInDns, int length);
/// <summary> /// Writes the layer to the buffer. /// </summary> /// <param name="buffer">The buffer to write the layer to.</param> /// <param name="offset">The offset in the buffer to start writing the layer at.</param> protected override void Write(byte[] buffer, int offset) { DnsDatagram.Write(buffer, offset, Id, IsResponse, OpCode, IsAuthoritativeAnswer, IsTruncated, IsRecursionDesired, IsRecursionAvailable, FutureUse, IsAuthenticData, IsCheckingDisabled, ResponseCode, Queries, Answers, Authorities, Additionals, DomainNameCompressionMode); }