1 files changed, 160 insertions, 0 deletions
diff --git a/SocketHttpListener/Net/WebSockets/HttpWebSocket.cs b/SocketHttpListener/Net/WebSockets/HttpWebSocket.cs
new file mode 100644
index 000000000..9dc9143f8
--- /dev/null
+++ b/SocketHttpListener/Net/WebSockets/HttpWebSocket.cs
@@ -0,0 +1,160 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Diagnostics.CodeAnalysis;
+using System.Security.Cryptography;
+using System.Threading;
+
+namespace SocketHttpListener.Net.WebSockets
+{
+    internal static partial class HttpWebSocket
+    {
+        internal const string SecWebSocketKeyGuid = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
+        internal const string WebSocketUpgradeToken = "websocket";
+        internal const int DefaultReceiveBufferSize = 16 * 1024;
+        internal const int DefaultClientSendBufferSize = 16 * 1024;
+
+        [SuppressMessage("Microsoft.Security", "CA5350", Justification = "SHA1 used only for hashing purposes, not for crypto.")]
+        internal static string GetSecWebSocketAcceptString(string secWebSocketKey)
+        {
+            string retVal;
+
+            // SHA1 used only for hashing purposes, not for crypto. Check here for FIPS compat.
+            using (SHA1 sha1 = SHA1.Create())
+            {
+                string acceptString = string.Concat(secWebSocketKey, HttpWebSocket.SecWebSocketKeyGuid);
+                byte[] toHash = Encoding.UTF8.GetBytes(acceptString);
+                retVal = Convert.ToBase64String(sha1.ComputeHash(toHash));
+            }
+
+            return retVal;
+        }
+
+        // return value here signifies if a Sec-WebSocket-Protocol header should be returned by the server. 
+        internal static bool ProcessWebSocketProtocolHeader(string clientSecWebSocketProtocol,
+            string subProtocol,
+            out string acceptProtocol)
+        {
+            acceptProtocol = string.Empty;
+            if (string.IsNullOrEmpty(clientSecWebSocketProtocol))
+            {
+                // client hasn't specified any Sec-WebSocket-Protocol header
+                if (subProtocol != null)
+                {
+                    // If the server specified _anything_ this isn't valid.
+                    throw new WebSocketException("UnsupportedProtocol");
+                }
+                // Treat empty and null from the server as the same thing here, server should not send headers. 
+                return false;
+            }
+
+            // here, we know the client specified something and it's non-empty.
+
+            if (subProtocol == null)
+            {
+                // client specified some protocols, server specified 'null'. So server should send headers.                 
+                return true;
+            }
+
+            // here, we know that the client has specified something, it's not empty
+            // and the server has specified exactly one protocol
+
+            string[] requestProtocols = clientSecWebSocketProtocol.Split(new char[] { ',' },
+                StringSplitOptions.RemoveEmptyEntries);
+            acceptProtocol = subProtocol;
+
+            // client specified protocols, serverOptions has exactly 1 non-empty entry. Check that 
+            // this exists in the list the client specified. 
+            for (int i = 0; i < requestProtocols.Length; i++)
+            {
+                string currentRequestProtocol = requestProtocols[i].Trim();
+                if (string.Equals(acceptProtocol, currentRequestProtocol, StringComparison.OrdinalIgnoreCase))
+                {
+                    return true;
+                }
+            }
+
+            throw new WebSocketException("net_WebSockets_AcceptUnsupportedProtocol");
+        }
+
+        internal static void ValidateOptions(string subProtocol, int receiveBufferSize, int sendBufferSize, TimeSpan keepAliveInterval)
+        {
+            if (subProtocol != null)
+            {
+                WebSocketValidate.ValidateSubprotocol(subProtocol);
+            }
+
+            if (receiveBufferSize < MinReceiveBufferSize)
+            {
+                throw new ArgumentOutOfRangeException("net_WebSockets_ArgumentOutOfRange_TooSmall");
+            }
+
+            if (sendBufferSize < MinSendBufferSize)
+            {
+                throw new ArgumentOutOfRangeException("net_WebSockets_ArgumentOutOfRange_TooSmall");
+            }
+
+            if (receiveBufferSize > MaxBufferSize)
+            {
+                throw new ArgumentOutOfRangeException("net_WebSockets_ArgumentOutOfRange_TooBig");
+            }
+
+            if (sendBufferSize > MaxBufferSize)
+            {
+                throw new ArgumentOutOfRangeException("net_WebSockets_ArgumentOutOfRange_TooBig");
+            }
+
+            if (keepAliveInterval < Timeout.InfiniteTimeSpan) // -1 millisecond
+            {
+                throw new ArgumentOutOfRangeException("net_WebSockets_ArgumentOutOfRange_TooSmall");
+            }
+        }
+
+        internal const int MinSendBufferSize = 16;
+        internal const int MinReceiveBufferSize = 256;
+        internal const int MaxBufferSize = 64 * 1024;
+
+        private static void ValidateWebSocketHeaders(HttpListenerContext context)
+        {
+            if (!WebSocketsSupported)
+            {
+                throw new PlatformNotSupportedException("net_WebSockets_UnsupportedPlatform");
+            }
+
+            if (!context.Request.IsWebSocketRequest)
+            {
+                throw new WebSocketException("net_WebSockets_AcceptNotAWebSocket");
+            }
+
+            string secWebSocketVersion = context.Request.Headers[HttpKnownHeaderNames.SecWebSocketVersion];
+            if (string.IsNullOrEmpty(secWebSocketVersion))
+            {
+                throw new WebSocketException("net_WebSockets_AcceptHeaderNotFound");
+            }
+
+            if (!string.Equals(secWebSocketVersion, SupportedVersion, StringComparison.OrdinalIgnoreCase))
+            {
+                throw new WebSocketException("net_WebSockets_AcceptUnsupportedWebSocketVersion");
+            }
+
+            string secWebSocketKey = context.Request.Headers[HttpKnownHeaderNames.SecWebSocketKey];
+            bool isSecWebSocketKeyInvalid = string.IsNullOrWhiteSpace(secWebSocketKey);
+            if (!isSecWebSocketKeyInvalid)
+            {
+                try
+                {
+                    // key must be 16 bytes then base64-encoded
+                    isSecWebSocketKeyInvalid = Convert.FromBase64String(secWebSocketKey).Length != 16;
+                }
+                catch
+                {
+                    isSecWebSocketKeyInvalid = true;
+                }
+            }
+            if (isSecWebSocketKeyInvalid)
+            {
+                throw new WebSocketException("net_WebSockets_AcceptHeaderNotFound");
+            }
+        }
+    }
+}