mcs/class/System/System.Net.WebSockets/ClientWebSocket.cs

   1 //
   2 // ClientWebSocket.cs
   3 //
   4 // Authors:
   5 //        Jérémie Laval <jeremie dot laval at xamarin dot com>
   6 //
   7 // Copyright 2013 Xamarin Inc (http://www.xamarin.com).
   8 //
   9 // Lightly inspired from WebSocket4Net distributed under the Apache License 2.0
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining a copy
  12 // of this software and associated documentation files (the "Software"), to deal
  13 // in the Software without restriction, including without limitation the rights
  14 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  15 // copies of the Software, and to permit persons to whom the Software is
  16 // furnished to do so, subject to the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be included in
  19 // all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  22 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  23 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  24 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  25 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  26 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  27 // THE SOFTWARE.
  28
  29
  30 using System;
  31 using System.Net;
  32 using System.Net.Sockets;
  33 using System.Security.Principal;
  34 using System.Security.Cryptography.X509Certificates;
  35 using System.Runtime.CompilerServices;
  36 using System.Collections.Generic;
  37 using System.Threading;
  38 using System.Threading.Tasks;
  39 using System.Globalization;
  40 using System.Text;
  41 using System.Security.Cryptography;
  42
  43 namespace System.Net.WebSockets
  44 {
  45         public class ClientWebSocket : WebSocket, IDisposable
  46         {
  47                 const string Magic = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
  48                 const string VersionTag = "13";
  49
  50                 ClientWebSocketOptions options;
  51                 WebSocketState state;
  52                 string subProtocol;
  53
  54                 HttpWebRequest req;
  55                 WebConnection connection;
  56                 Socket underlyingSocket;
  57
  58                 Random random = new Random ();
  59
  60                 const int HeaderMaxLength = 14;
  61                 byte[] headerBuffer;
  62                 byte[] sendBuffer;
  63                 long remaining;
  64
  65                 public ClientWebSocket ()
  66                 {
  67                         options = new ClientWebSocketOptions ();
  68                         state = WebSocketState.None;
  69                         headerBuffer = new byte[HeaderMaxLength];
  70                 }
  71
  72                 public override void Dispose ()
  73                 {
  74                         if (connection != null)
  75                                 connection.Close (false);
  76                 }
  77
  78                 [MonoTODO]
  79                 public override void Abort ()
  80                 {
  81                         throw new NotImplementedException ();
  82                 }
  83
  84                 public ClientWebSocketOptions Options {
  85                         get {
  86                                 return options;
  87                         }
  88                 }
  89
  90                 public override WebSocketState State {
  91                         get {
  92                                 return state;
  93                         }
  94                 }
  95
  96                 public override WebSocketCloseStatus? CloseStatus {
  97                         get {
  98                                 if (state != WebSocketState.Closed)
  99                                         return (WebSocketCloseStatus?)null;
 100                                 return WebSocketCloseStatus.Empty;
 101                         }
 102                 }
 103
 104                 public override string CloseStatusDescription {
 105                         get {
 106                                 return null;
 107                         }
 108                 }
 109
 110                 public override string SubProtocol {
 111                         get {
 112                                 return subProtocol;
 113                         }
 114                 }
 115
 116                 public async Task ConnectAsync (Uri uri, CancellationToken cancellationToken)
 117                 {
 118                         state = WebSocketState.Connecting;
 119                         var httpUri = new UriBuilder (uri);
 120                         if (uri.Scheme == "wss")
 121                                 httpUri.Scheme = "https";
 122                         else
 123                                 httpUri.Scheme = "http";
 124                         req = (HttpWebRequest)WebRequest.Create (httpUri.Uri);
 125                         req.ReuseConnection = true;
 126                         if (options.Cookies != null)
 127                                 req.CookieContainer = options.Cookies;
 128
 129                         if (options.CustomRequestHeaders.Count > 0) {
 130                                 foreach (var header in options.CustomRequestHeaders)
 131                                         req.Headers[header.Key] = header.Value;
 132                         }
 133
 134                         var secKey = Convert.ToBase64String (Encoding.ASCII.GetBytes (Guid.NewGuid ().ToString ().Substring (0, 16)));
 135                         string expectedAccept = Convert.ToBase64String (SHA1.Create ().ComputeHash (Encoding.ASCII.GetBytes (secKey + Magic)));
 136
 137                         req.Headers["Upgrade"] = "WebSocket";
 138                         req.Headers["Sec-WebSocket-Version"] = VersionTag;
 139                         req.Headers["Sec-WebSocket-Key"] = secKey;
 140                         req.Headers["Sec-WebSocket-Origin"] = uri.Host;
 141                         if (options.SubProtocols.Count > 0)
 142                                 req.Headers["Sec-WebSocket-Protocol"] = string.Join (",", options.SubProtocols);
 143
 144                         if (options.Credentials != null)
 145                                 req.Credentials = options.Credentials;
 146                         if (options.ClientCertificates != null)
 147                                 req.ClientCertificates = options.ClientCertificates;
 148                         if (options.Proxy != null)
 149                                 req.Proxy = options.Proxy;
 150                         req.UseDefaultCredentials = options.UseDefaultCredentials;
 151                         req.Connection = "Upgrade";
 152
 153                         HttpWebResponse resp = null;
 154                         try {
 155                                 resp = (HttpWebResponse)(await req.GetResponseAsync ().ConfigureAwait (false));
 156                         } catch (Exception e) {
 157                                 throw new WebSocketException (WebSocketError.Success, e);
 158                         }
 159
 160                         connection = req.StoredConnection;
 161                         underlyingSocket = connection.socket;
 162
 163                         if (resp.StatusCode != HttpStatusCode.SwitchingProtocols)
 164                                 throw new WebSocketException ("The server returned status code '" + (int)resp.StatusCode + "' when status code '101' was expected");
 165                         if (!string.Equals (resp.Headers["Upgrade"], "WebSocket", StringComparison.OrdinalIgnoreCase)
 166                                 || !string.Equals (resp.Headers["Connection"], "Upgrade", StringComparison.OrdinalIgnoreCase)
 167                                 || !string.Equals (resp.Headers["Sec-WebSocket-Accept"], expectedAccept))
 168                                 throw new WebSocketException ("HTTP header error during handshake");
 169                         if (resp.Headers["Sec-WebSocket-Protocol"] != null) {
 170                                 if (!options.SubProtocols.Contains (resp.Headers["Sec-WebSocket-Protocol"]))
 171                                         throw new WebSocketException (WebSocketError.UnsupportedProtocol);
 172                                 subProtocol = resp.Headers["Sec-WebSocket-Protocol"];
 173                         }
 174
 175                         state = WebSocketState.Open;
 176                 }
 177
 178                 public override Task SendAsync (ArraySegment<byte> buffer, WebSocketMessageType messageType, bool endOfMessage, CancellationToken cancellationToken)
 179                 {
 180                         EnsureWebSocketConnected ();
 181                         ValidateArraySegment (buffer);
 182                         if (connection == null)
 183                                 throw new WebSocketException (WebSocketError.Faulted);
 184                         var count = Math.Max (options.SendBufferSize, buffer.Count) + HeaderMaxLength;
 185                         if (sendBuffer == null || sendBuffer.Length != count)
 186                                 sendBuffer = new byte[count];
 187                         return Task.Run (() => {
 188                                 EnsureWebSocketState (WebSocketState.Open, WebSocketState.CloseReceived);
 189                                 var maskOffset = WriteHeader (messageType, buffer, endOfMessage);
 190
 191                                 if (buffer.Count > 0)
 192                                         MaskData (buffer, maskOffset);
 193                                 //underlyingSocket.Send (headerBuffer, 0, maskOffset + 4, SocketFlags.None);
 194                                 var headerLength = maskOffset + 4;
 195                                 Array.Copy (headerBuffer, sendBuffer, headerLength);
 196                                 underlyingSocket.Send (sendBuffer, 0, buffer.Count + headerLength, SocketFlags.None);
 197                         });
 198                 }
 199
 200                 const int messageTypeText = 1;
 201                 const int messageTypeBinary = 2;
 202                 const int messageTypeClose = 8;
 203
 204                 static WebSocketMessageType WireToMessageType (byte msgType)
 205                 {
 206
 207                         if (msgType == messageTypeText)
 208                                 return WebSocketMessageType.Text;
 209                         if (msgType == messageTypeBinary)
 210                                 return WebSocketMessageType.Binary;
 211                         return WebSocketMessageType.Close;
 212                 }
 213
 214                 static byte MessageTypeToWire (WebSocketMessageType type)
 215                 {
 216                         if (type == WebSocketMessageType.Text)
 217                                 return messageTypeText;
 218                         if (type == WebSocketMessageType.Binary)
 219                                 return messageTypeBinary;
 220                         return messageTypeClose;
 221                 }
 222
 223                 public override Task<WebSocketReceiveResult> ReceiveAsync (ArraySegment<byte> buffer, CancellationToken cancellationToken)
 224                 {
 225                         EnsureWebSocketConnected ();
 226                         ValidateArraySegment (buffer);
 227                         return Task.Run (() => {
 228                                 EnsureWebSocketState (WebSocketState.Open, WebSocketState.CloseSent);
 229
 230                                 bool isLast;
 231                                 WebSocketMessageType type;
 232                                 long length;
 233
 234                                 if (remaining == 0) {
 235                                         // First read the two first bytes to know what we are doing next
 236                                         connection.Read (req, headerBuffer, 0, 2);
 237                                         isLast = (headerBuffer[0] >> 7) > 0;
 238                                         var isMasked = (headerBuffer[1] >> 7) > 0;
 239                                         int mask = 0;
 240                                         type = WireToMessageType ((byte)(headerBuffer[0] & 0xF));
 241                                         length = headerBuffer[1] & 0x7F;
 242                                         int offset = 0;
 243                                         if (length == 126) {
 244                                                 offset = 2;
 245                                                 connection.Read (req, headerBuffer, 2, offset);
 246                                         length = (headerBuffer[2] << 8) | headerBuffer[3];
 247                                         } else if (length == 127) {
 248                                                 offset = 8;
 249                                                 connection.Read (req, headerBuffer, 2, offset);
 250                                                 length = 0;
 251                                                 for (int i = 2; i <= 9; i++)
 252                                                         length = (length << 8) | headerBuffer[i];
 253                                         }
 254
 255                                         if (isMasked) {
 256                                                 connection.Read (req, headerBuffer, 2 + offset, 4);
 257                                                 for (int i = 0; i < 4; i++) {
 258                                                         var pos = i + offset + 2;
 259                                                         mask = (mask << 8) | headerBuffer[pos];
 260                                                 }
 261                                         }
 262                                 } else {
 263                                         isLast = (headerBuffer[0] >> 7) > 0;
 264                                         type = WireToMessageType ((byte)(headerBuffer[0] & 0xF));
 265                                         length = remaining;
 266                                 }
 267
 268                                 if (type == WebSocketMessageType.Close) {
 269                                         state = WebSocketState.Closed;
 270                                         var tmpBuffer = new byte[length];
 271                                         connection.Read (req, tmpBuffer, 0, tmpBuffer.Length);
 272                                         var closeStatus = (WebSocketCloseStatus)(tmpBuffer[0] << 8 | tmpBuffer[1]);
 273                                         var closeDesc = tmpBuffer.Length > 2 ? Encoding.UTF8.GetString (tmpBuffer, 2, tmpBuffer.Length - 2) : string.Empty;
 274                                         return new WebSocketReceiveResult ((int)length, type, isLast, closeStatus, closeDesc);
 275                                 } else {
 276                                         var readLength = (int)(buffer.Count < length ? buffer.Count : length);
 277                                         connection.Read (req, buffer.Array, buffer.Offset, readLength);
 278                                         remaining = length - readLength;
 279
 280                                         return new WebSocketReceiveResult ((int)readLength, type, isLast && remaining == 0);
 281                                 }
 282                         });
 283                 }
 284
 285                 // The damn difference between those two methods is that CloseAsync will wait for server acknowledgement before completing
 286                 // while CloseOutputAsync will send the close packet and simply complete.
 287
 288                 public async override Task CloseAsync (WebSocketCloseStatus closeStatus, string statusDescription, CancellationToken cancellationToken)
 289                 {
 290                         EnsureWebSocketConnected ();
 291                         await SendCloseFrame (closeStatus, statusDescription, cancellationToken).ConfigureAwait (false);
 292                         state = WebSocketState.CloseSent;
 293                         // TODO: figure what's exceptions are thrown if the server returns something faulty here
 294                         await ReceiveAsync (new ArraySegment<byte> (new byte[0]), cancellationToken).ConfigureAwait (false);
 295                         state = WebSocketState.Closed;
 296                 }
 297
 298                 public async override Task CloseOutputAsync (WebSocketCloseStatus closeStatus, string statusDescription, CancellationToken cancellationToken)
 299                 {
 300                         EnsureWebSocketConnected ();
 301                         await SendCloseFrame (closeStatus, statusDescription, cancellationToken).ConfigureAwait (false);
 302                         state = WebSocketState.CloseSent;
 303                 }
 304
 305                 async Task SendCloseFrame (WebSocketCloseStatus closeStatus, string statusDescription, CancellationToken cancellationToken)
 306                 {
 307                         var statusDescBuffer = string.IsNullOrEmpty (statusDescription) ? new byte[2] : new byte[2 + Encoding.UTF8.GetByteCount (statusDescription)];
 308                         statusDescBuffer[0] = (byte)(((ushort)closeStatus) >> 8);
 309                         statusDescBuffer[1] = (byte)(((ushort)closeStatus) & 0xFF);
 310                         if (!string.IsNullOrEmpty (statusDescription))
 311                                 Encoding.UTF8.GetBytes (statusDescription, 0, statusDescription.Length, statusDescBuffer, 2);
 312                         await SendAsync (new ArraySegment<byte> (statusDescBuffer), WebSocketMessageType.Close, true, cancellationToken).ConfigureAwait (false);
 313                 }
 314
 315                 int WriteHeader (WebSocketMessageType type, ArraySegment<byte> buffer, bool endOfMessage)
 316                 {
 317                         var opCode = MessageTypeToWire (type);
 318                         var length = buffer.Count;
 319
 320                         headerBuffer[0] = (byte)(opCode | (endOfMessage ? 0x80 : 0));
 321                         if (length < 126) {
 322                                 headerBuffer[1] = (byte)length;
 323                         } else if (length <= ushort.MaxValue) {
 324                                 headerBuffer[1] = (byte)126;
 325                                 headerBuffer[2] = (byte)(length / 256);
 326                                 headerBuffer[3] = (byte)(length % 256);
 327                         } else {
 328                                 headerBuffer[1] = (byte)127;
 329
 330                                 int left = length;
 331                                 int unit = 256;
 332
 333                                 for (int i = 9; i > 1; i--) {
 334                                         headerBuffer[i] = (byte)(left % unit);
 335                                         left = left / unit;
 336                                 }
 337                         }
 338
 339                         var l = Math.Max (0, headerBuffer[1] - 125);
 340                         var maskOffset = 2 + l * l * 2;
 341                         GenerateMask (headerBuffer, maskOffset);
 342
 343                         // Since we are client only, we always mask the payload
 344                         headerBuffer[1] |= 0x80;
 345
 346                         return maskOffset;
 347                 }
 348
 349                 void GenerateMask (byte[] mask, int offset)
 350                 {
 351                         mask[offset + 0] = (byte)random.Next (0, 255);
 352                         mask[offset + 1] = (byte)random.Next (0, 255);
 353                         mask[offset + 2] = (byte)random.Next (0, 255);
 354                         mask[offset + 3] = (byte)random.Next (0, 255);
 355                 }
 356
 357                 void MaskData (ArraySegment<byte> buffer, int maskOffset)
 358                 {
 359                         var sendBufferOffset = maskOffset + 4;
 360                         for (var i = 0; i < buffer.Count; i++)
 361                                 sendBuffer[i + sendBufferOffset] = (byte)(buffer.Array[buffer.Offset + i] ^ headerBuffer[maskOffset + (i % 4)]);
 362                 }
 363
 364                 void EnsureWebSocketConnected ()
 365                 {
 366                         if (state < WebSocketState.Open)
 367                                 throw new InvalidOperationException ("The WebSocket is not connected");
 368                 }
 369
 370                 void EnsureWebSocketState (params WebSocketState[] validStates)
 371                 {
 372                         foreach (var validState in validStates)
 373                                 if (state == validState)
 374                                         return;
 375                         throw new WebSocketException ("The WebSocket is in an invalid state ('" + state + "') for this operation. Valid states are: " + string.Join (", ", validStates));
 376                 }
 377
 378                 void ValidateArraySegment (ArraySegment<byte> segment)
 379                 {
 380                         if (segment.Array == null)
 381                                 throw new ArgumentNullException ("buffer.Array");
 382                         if (segment.Offset < 0)
 383                                 throw new ArgumentOutOfRangeException ("buffer.Offset");
 384                         if (segment.Offset + segment.Count > segment.Array.Length)
 385                                 throw new ArgumentOutOfRangeException ("buffer.Count");
 386                 }
 387         }
 388 }
 389