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Assets/Mirror/Transports/KCP/kcp2k/highlevel/KcpHeader.cs

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+using System;
+
+namespace kcp2k
+{
+    // header for messages processed by kcp.
+    // this is NOT for the raw receive messages(!) because handshake/disconnect
+    // need to be sent reliably. it's not enough to have those in rawreceive
+    // because those messages might get lost without being resent!
+    public enum KcpHeaderReliable : byte
+    {
+        // don't react on 0x00. might help to filter out random noise.
+        Hello      = 1,
+        // ping goes over reliable & KcpHeader for now. could go over unreliable
+        // too. there is no real difference except that this is easier because
+        // we already have a KcpHeader for reliable messages.
+        // ping is only used to keep it alive, so latency doesn't matter.
+        Ping       = 2,
+        Data       = 3,
+    }
+
+    public enum KcpHeaderUnreliable : byte
+    {
+        // users may send unreliable messages
+        Data = 4,
+        // disconnect always goes through rapid fire unreliable (glenn fielder)
+        Disconnect = 5,
+    }
+
+    // save convert the enums from/to byte.
+    // attackers may attempt to send invalid values, so '255' may not convert.
+    public static class KcpHeader
+    {
+        public static bool ParseReliable(byte value, out KcpHeaderReliable header)
+        {
+            if (Enum.IsDefined(typeof(KcpHeaderReliable), value))
+            {
+                header = (KcpHeaderReliable)value;
+                return true;
+            }
+
+            header = KcpHeaderReliable.Ping; // any default
+            return false;
+        }
+
+        public static bool ParseUnreliable(byte value, out KcpHeaderUnreliable header)
+        {
+            if (Enum.IsDefined(typeof(KcpHeaderUnreliable), value))
+            {
+                header = (KcpHeaderUnreliable)value;
+                return true;
+            }
+
+            header = KcpHeaderUnreliable.Disconnect; // any default
+            return false;
+        }
+    }
+}