Reolve #1 - Implement HTTPS and SVCB records

TinyDNS/Records/ResourceRecord.cs

@@ -67,6 +67,10 @@ public static ResourceRecord Parse(Span<byte> buffer, ref int pos)
                 case DNSRecordType.SOA:
                     record = new SOARecord(header, buffer, ref pos);
                     break;
+                case DNSRecordType.HTTPS:
+                case DNSRecordType.SVCB:
+                    record = new SvcbRecord(header, buffer, ref pos);
+                    break;
                 default:
                     record = new UnsupportedRecord(header, buffer, ref pos);
                     break;

TinyDNS/Records/SVCBRecord.cs

@@ -0,0 +1,149 @@
+// TinyDNS Copyright (C) 2024 
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or any later version.
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY, without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU Affero General Public License for more details.
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+using System;
+using System.Buffers.Binary;
+using System.Net;
+using System.Text;
+using TinyDNS.Enums;
+
+namespace TinyDNS.Records
+{
+    public class SvcbRecord : ResourceRecord
+    {
+        public int ServicePriority { get; }
+        public List<string> TargetName { get; }
+        public Dictionary<string, List<string>> Parameters { get; }
+
+        internal SvcbRecord(ResourceRecordHeader header, Span<byte> buffer, ref int pos) : base(header)
+        {
+            Dictionary<string, List<string>> param = new();
+            ushort rLen = BinaryPrimitives.ReadUInt16BigEndian(buffer.Slice(pos, 2));
+            pos += 2;
+            int initialPos = pos;
+            ServicePriority = BinaryPrimitives.ReadUInt16BigEndian(buffer.Slice(pos, 2));
+            pos += 2;
+            TargetName = DomainParser.Read(buffer, ref pos);
+            rLen -= (ushort)(pos - initialPos);
+            while (rLen > 0)
+            {
+                ushort key = BinaryPrimitives.ReadUInt16BigEndian(buffer.Slice(pos, 2));
+                pos += 2;
+                ushort len = BinaryPrimitives.ReadUInt16BigEndian(buffer.Slice(pos, 2));
+                pos += 2;
+                rLen -= 4;
+                if (len > 0)
+                {
+                    param.Add(GetKey(key), GetValue(key, buffer.Slice(pos, len)));
+                    pos += len;
+                    rLen -= len;
+                }
+                else
+                    param.Add(GetKey(key), []);
+            }
+            if (rLen < 0)
+                throw new InvalidDataException("Currupted SVCB record");
+            Parameters = param;
+        }
+
+        public SvcbRecord(Dictionary<string, List<string>> @params, List<string> targetName, ushort priority, List<string> labels, DNSClass @class, uint ttl) : base(labels, DNSRecordType.SVCB, @class, ttl)
+        {
+            Parameters = @params;
+            TargetName = targetName;
+            ServicePriority = priority;
+        }
+
+        public override bool Equals(ResourceRecord? other)
+        {
+            if (other is SvcbRecord otherSvcb)
+                return base.Equals(other) && Parameters.Equals(otherSvcb.Parameters);
+            return false;
+        }
+
+        private string GetKey(ushort keyIndex)
+        {
+            switch (keyIndex)
+            {
+                case 0:
+                    return "mandatory";
+                case 1:
+                    return "alpn";
+                case 2:
+                    return "no-default-alpn";
+                case 3:
+                    return "port";
+                case 4:
+                    return "ipv4hint";
+                case 5:
+                    return "ech";
+                case 6:
+                    return "ipv6hint";
+                case 7:
+                    return "dohpath";
+                case 8:
+                    return "ohttp";
+                default:
+                    return "unknown";
+            }
+        }
+
+        private List<string> GetValue(ushort key, Span<byte> span)
+        {
+            List<string> strings = [];
+            switch (key)
+            {
+                case 1:
+                case 2:
+                    int pos = 0;
+                    while (pos < span.Length)
+                    {
+                        byte len = span[pos++];
+                        if (len > 0)
+                        {
+                            strings.Add(Encoding.UTF8.GetString(span.Slice(pos, len)));
+                            pos += len;
+                        }
+                    }
+                    break;
+                case 3:
+                    strings.Add(BinaryPrimitives.ReadUInt16BigEndian(span).ToString());
+                    break;
+                case 4:
+                    for (int i = 0; i < span.Length; i += 4)
+                        strings.Add(new IPAddress(span.Slice(i, 4)).ToString());
+                    break;
+                case 6:
+                    for (int i = 0; i < span.Length; i += 16)
+                        strings.Add(new IPAddress(span.Slice(i, 16)).ToString());
+                    break;
+                default:
+                    strings.Add(Encoding.UTF8.GetString(span));
+                    break;
+            }
+            return strings;
+        }
+
+        public override string ToString()
+        {
+            StringBuilder sb = new StringBuilder();
+            foreach (var kvp in Parameters)
+            {
+                if (sb.Length > 0)
+                    sb.Append(' ');
+                sb.Append(kvp.Key);
+                sb.Append("=");
+                sb.Append(string.Join(',', kvp.Value));
+            }
+            return base.ToString() + $"\t{sb}";
+        }
+    }
+}