feat(MasterFile): handle unknown RDATA

src/MasterReader.cs

@@ -124,6 +124,49 @@ public IPAddress ReadIPAddress(int length = 4)
             return IPAddress.Parse(ReadToken());
         }
 
+        /// <summary>
+        ///   Read hex encoded RDATA.
+        /// </summary>
+        /// <returns>
+        ///   A byte array containing the RDATA.
+        /// </returns>
+        /// <remarks>
+        ///   See <see href="https://tools.ietf.org/html/rfc3597#section-5"/> for all
+        ///   the details.
+        /// </remarks>
+        public byte[] ReadResourceData()
+        {
+            var leadin = ReadToken();
+            if (leadin != "#")
+                throw new FormatException($"Expected RDATA leadin '\\#', not '{leadin}'.");
+            var length = ReadUInt32();
+            if (length == 0)
+                return new byte[0];
+
+            // Get the hex string.
+            var sb = new StringBuilder();
+            while (sb.Length < length * 2)
+            {
+                var word = ReadToken();
+                if (word.Length == 0)
+                    break;
+                if (word.Length % 2 != 0)
+                    throw new FormatException($"The hex word ('{word}') must have an even number of digits.");
+                sb.Append(word);
+            }
+            if (sb.Length != length * 2)
+                throw new FormatException("Wrong number of RDATA hex digits.");
+
+            // Convert hex string into byte array.
+            var bytes = new byte[length];
+            for (int i = 0; i < length * 2; i += 2)
+            {
+                bytes[i / 2] = Convert.ToByte(sb.ToString(i, 2), 16);
+            }
+
+            return bytes;
+        }
+
         /// <summary>
         ///   Read a resource record.
         /// </summary>
@@ -290,6 +333,7 @@ string ReadToken()
                     c = text.Read();
                     // TODO: \DDD
                     sb.Append((char)c);
+                    skipWhitespace = false;
                     continue;
                 }
 

src/NULLRecord.cs

@@ -39,7 +39,7 @@ protected override void ReadData(DnsReader reader, int length)
         /// <inheritdoc />
         internal override void ReadData(MasterReader reader)
         {
-            Data = Convert.FromBase64String(reader.ReadString());
+            Data = reader.ReadResourceData();
         }
 
         /// <inheritdoc />

src/ResourceRecord.cs

@@ -339,13 +339,18 @@ public void Write(TextWriter writer)
         /// <remarks>
         ///   Derived classes should implement this method.
         ///   <para>
-        ///   By default, this will write the base64 encoding of
-        ///   the <see cref="GetData">RDATA</see>.
+        ///   By default, this will write the hex encoding of
+        ///   the <see cref="GetData">RDATA</see> preceeded by
+        ///   "\#" and the number integer bytes.
         ///   </para>
         /// </remarks>
         protected virtual void WriteData(TextWriter writer)
         {
-            writer.Write(Convert.ToBase64String(GetData()));
+            var rdata = GetData();
+            writer.Write("\\# ");
+            writer.Write(rdata.Length);
+            writer.Write(' ');
+            writer.Write(BitConverter.ToString(rdata).Replace("-", ""));
         }
 
         /// <summary>

src/UnknownRecord.cs

@@ -22,6 +22,12 @@ protected override void ReadData(DnsReader reader, int length)
             Data = reader.ReadBytes(length);
         }
 
+        /// <inheritdoc />
+        internal override void ReadData(MasterReader reader)
+        {
+            Data = reader.ReadResourceData();
+        }
+
         /// <inheritdoc />
         protected override void WriteData(DnsWriter writer)
         {

test/MasterReaderTest.cs

@@ -74,7 +74,7 @@ public void ReadResourceWithUnknownClass()
         [TestMethod]
         public void ReadResourceWithUnknownType()
         {
-            var reader = new MasterReader(new StringReader("me CH TYPE1234"));
+            var reader = new MasterReader(new StringReader("me CH TYPE1234 \\# 0"));
             var resource = reader.ReadResourceRecord();
             Assert.AreEqual("me", resource.Name);
             Assert.AreEqual(Class.CH, resource.Class);
@@ -185,5 +185,57 @@ example.com.  IN  SOA   ns.example.com. username.example.com. ( 2007120710 1 2 4
             }
             Assert.AreEqual(15, resources.Count);
         }
+
+        [TestMethod]
+        public void ReadResourceData()
+        {
+            var reader = new MasterReader(new StringReader("\\# 0"));
+            var rdata = reader.ReadResourceData();
+            Assert.AreEqual(0, rdata.Length);
+
+            reader = new MasterReader(new StringReader("\\# 3 abcdef"));
+            rdata = reader.ReadResourceData();
+            CollectionAssert.AreEqual(new byte[] { 0xab, 0xcd, 0xef }, rdata);
+
+            reader = new MasterReader(new StringReader("\\# 3 ab cd ef"));
+            rdata = reader.ReadResourceData();
+            CollectionAssert.AreEqual(new byte[] { 0xab, 0xcd, 0xef }, rdata);
+
+            reader = new MasterReader(new StringReader("\\# 3 abcd (\r\n  ef )"));
+            rdata = reader.ReadResourceData();
+            CollectionAssert.AreEqual(new byte[] { 0xab, 0xcd, 0xef }, rdata);
+        }
+
+        [TestMethod]
+        [ExpectedException(typeof(FormatException))]
+        public void ReadResourceData_MissingLeadin()
+        {
+            var reader = new MasterReader(new StringReader("0"));
+            var _ = reader.ReadResourceData();
+        }
+
+        [TestMethod]
+        [ExpectedException(typeof(FormatException))]
+        public void ReadResourceData_BadHex_BadDigit()
+        {
+            var reader = new MasterReader(new StringReader("\\# 3 ab cd ez"));
+            var _ = reader.ReadResourceData();
+        }
+
+        [TestMethod]
+        [ExpectedException(typeof(FormatException))]
+        public void ReadResourceData_BadHex_NotEven()
+        {
+            var reader = new MasterReader(new StringReader("\\# 3 ab cd e"));
+            var _ = reader.ReadResourceData();
+        }
+
+        [TestMethod]
+        [ExpectedException(typeof(FormatException))]
+        public void ReadResourceData_BadHex_TooFew()
+        {
+            var reader = new MasterReader(new StringReader("\\# 3 abcd"));
+            var _ = reader.ReadResourceData();
+        }
     }
 }

test/ResourceRecordTest.cs

@@ -141,23 +141,23 @@ public void Stringing()
                 Name = "x.emanon.org",
                 Type = DnsType.A
             };
-            Assert.AreEqual("x.emanon.org IN A", a.ToString());
+            Assert.AreEqual("x.emanon.org IN A \\# 0", a.ToString());
 
             a = new ResourceRecord
             {
                 Name = "x.emanon.org",
                 Type = DnsType.A,
                 Class = Class.CH
             };
-            Assert.AreEqual("x.emanon.org CH A", a.ToString());
+            Assert.AreEqual("x.emanon.org CH A \\# 0", a.ToString());
 
             a = new ResourceRecord
             {
                 Name = "x.emanon.org",
                 Type = DnsType.A,
                 TTL = TimeSpan.FromSeconds(123)
             };
-            Assert.AreEqual("x.emanon.org 123 IN A", a.ToString());
+            Assert.AreEqual("x.emanon.org 123 IN A \\# 0", a.ToString());
         }
 
         [TestMethod]
@@ -192,7 +192,7 @@ public void Stringing_UnknownClass()
                 Class = (Class)1234,
                 Type = DnsType.A
             };
-            Assert.AreEqual("x.emanon.org CLASS1234 A", a.ToString());
+            Assert.AreEqual("x.emanon.org CLASS1234 A \\# 0", a.ToString());
         }
 
         [TestMethod]
@@ -203,7 +203,7 @@ public void Stringing_UnknownType()
                 Name = "x.emanon.org",
                 Type = (DnsType)1234
             };
-            Assert.AreEqual("x.emanon.org IN TYPE1234", a.ToString());
+            Assert.AreEqual("x.emanon.org IN TYPE1234 \\# 0", a.ToString());
         }
     }
 }

test/UnknownRecordTest.cs

@@ -44,5 +44,23 @@ public void Equality()
             Assert.IsFalse(a.Equals(null));
         }
 
+        [TestMethod]
+        public void Roundtrip_Master()
+        {
+            var a = new UnknownRecord
+            {
+                Name = "a.example",
+                Class = (Class)32,
+                Type = (DnsType)731,
+                Data = new byte[] { 0xab, 0xcd, 0xef, 0x01, 0x23, 0x45 }
+            };
+            var b = (UnknownRecord)new ResourceRecord().Read(a.ToString());
+            Assert.AreEqual(a.Name, b.Name);
+            Assert.AreEqual(a.Class, b.Class);
+            Assert.AreEqual(a.Type, b.Type);
+            Assert.AreEqual(a.TTL, b.TTL);
+            CollectionAssert.AreEqual(a.Data, b.Data);
+        }
+
     }
 }