done

Netch/3rd/DnsClient.NET/Protocol/CNameRecord.cs

@@ -0,0 +1,56 @@
+using System;
+
+namespace DnsClient.Protocol
+{
+    /*
+    https://tools.ietf.org/html/rfc1035#section-3.3.1:
+    3.3.1. CNAME RDATA format
+
+        +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+        /                     CNAME                     /
+        /                                               /
+        +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+
+    where:
+
+    CNAME           A <domain-name> which specifies the canonical or primary
+                    name for the owner.  The owner name is an alias.
+
+    CNAME RRs cause no additional section processing, but name servers may
+    choose to restart the query at the canonical name in certain cases.  See
+    the description of name server logic in [RFC-1034] for details.
+
+     */
+
+    /// <summary>
+    /// A <see cref="DnsResourceRecord"/> repesenting the canonical name for an alias.
+    /// </summary>
+    /// <seealso href="https://tools.ietf.org/html/rfc1035#section-3.3.1">RFC 1035</seealso>
+    public class CNameRecord : DnsResourceRecord
+    {
+        /// <summary>
+        /// Gets the canonical name for an alias.
+        /// </summary>
+        /// <value>
+        /// The canonical name.
+        /// </value>
+        public DnsString CanonicalName { get; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CNameRecord"/> class.
+        /// </summary>
+        /// <param name="info">The information.</param>
+        /// <param name="canonicalName">The canonical name.</param>
+        /// <exception cref="System.ArgumentNullException">If <paramref name="canonicalName"/> or <paramref name="info"/> is null.</exception>
+        public CNameRecord(ResourceRecordInfo info, DnsString canonicalName)
+            : base(info)
+        {
+            CanonicalName = canonicalName ?? throw new ArgumentNullException(nameof(canonicalName));
+        }
+
+        private protected override string RecordToString()
+        {
+            return CanonicalName.Value;
+        }
+    }
+}