mcs/class/System/System.Net.NetworkInformation/Ping.cs

   1 //
   2 // System.Net.NetworkInformation.Ping
   3 //
   4 // Authors:
   5 //      Gonzalo Paniagua Javier (gonzalo@novell.com)
   6 //      Atsushi Enomoto (atsushi@ximian.com)
   7 //
   8 // Copyright (c) 2006-2007 Novell, Inc. (http://www.novell.com)
   9 // Copyright 2015 Xamarin Inc.
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System;
  32 using System.IO;
  33 using System.Text;
  34 using System.Diagnostics;
  35 using System.Globalization;
  36 using System.ComponentModel;
  37 using System.Net.Sockets;
  38 using System.Security.Principal;
  39 using System.Security.Cryptography;
  40 using System.Runtime.InteropServices;
  41 using System.Threading;
  42 using System.Threading.Tasks;
  43
  44 namespace System.Net.NetworkInformation {
  45         [MonoTODO ("IPv6 support is missing")]
  46         public class Ping : Component, IDisposable
  47         {
  48 #if !MONOTOUCH
  49                 [StructLayout(LayoutKind.Sequential)]
  50                 struct cap_user_header_t
  51                 {
  52                         public UInt32 version;
  53                         public Int32 pid;
  54                 };
  55
  56                 [StructLayout(LayoutKind.Sequential)]
  57                 struct cap_user_data_t
  58                 {
  59                         public UInt32 effective;
  60                         public UInt32 permitted;
  61                         public UInt32 inheritable;
  62                 }
  63
  64                 const int DefaultCount = 1;
  65                 static readonly string [] PingBinPaths = new string [] {
  66                         "/bin/ping",
  67                         "/sbin/ping",
  68                         "/usr/sbin/ping",
  69 #if MONODROID
  70                         "/system/bin/ping"
  71 #endif
  72                 };
  73                 static readonly string PingBinPath;
  74                 static bool canSendPrivileged;
  75 #endif
  76                 const int default_timeout = 4000; // 4 sec.
  77                 ushort identifier;
  78
  79                 // Request 32-bit capabilities by using version 1
  80                 const UInt32 _LINUX_CAPABILITY_VERSION_1 = 0x19980330;
  81
  82                 static readonly byte [] default_buffer = new byte [0];
  83
  84
  85                 BackgroundWorker worker;
  86                 object user_async_state;
  87                 CancellationTokenSource cts;
  88
  89                 public event PingCompletedEventHandler PingCompleted;
  90
  91 #if !MONOTOUCH && !ORBIS
  92                 static Ping ()
  93                 {
  94                         if (Environment.OSVersion.Platform == PlatformID.Unix) {
  95                                 CheckLinuxCapabilities ();
  96                                 if (!canSendPrivileged && WindowsIdentity.GetCurrent ().Name == "root")
  97                                         canSendPrivileged = true;
  98
  99                                 // Since different Unix systems can have different path to bin, we try some
 100                                 // of the known ones.
 101                                 foreach (string ping_path in PingBinPaths)
 102                                         if (File.Exists (ping_path)) {
 103                                                 PingBinPath = ping_path;
 104                                                 break;
 105                                         }
 106                         }
 107                         else
 108                                 canSendPrivileged = true;
 109
 110                         if (PingBinPath == null)
 111                                 PingBinPath = "/bin/ping"; // default, fallback value
 112                 }
 113 #endif
 114
 115                 public Ping ()
 116                 {
 117                         // Generate a new random 16 bit identifier for every ping
 118                         RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider ();
 119                         byte [] randomIdentifier = new byte [2];
 120                         rng.GetBytes (randomIdentifier);
 121                         identifier = (ushort)(randomIdentifier [0] + (randomIdentifier [1] << 8));
 122                 }
 123
 124 #if !MONOTOUCH && !ORBIS
 125                 [DllImport ("libc", EntryPoint="capget")]
 126                 static extern int capget (ref cap_user_header_t header, ref cap_user_data_t data);
 127
 128                 static void CheckLinuxCapabilities ()
 129                 {
 130                         try {
 131                                 cap_user_header_t header = new cap_user_header_t ();
 132                                 cap_user_data_t data = new cap_user_data_t ();
 133
 134                                 header.version = _LINUX_CAPABILITY_VERSION_1;
 135
 136                                 int ret = -1;
 137
 138                                 try {
 139                                         ret = capget (ref header, ref data);
 140                                 } catch (Exception) {
 141                                 }
 142
 143                                 if (ret == -1)
 144                                         return;
 145
 146                                 canSendPrivileged = (data.effective & (1 << 13)) != 0;
 147                         } catch {
 148                                 canSendPrivileged = false;
 149                         }
 150                 }
 151 #endif
 152
 153                 void IDisposable.Dispose ()
 154                 {
 155                 }
 156
 157                 protected void OnPingCompleted (PingCompletedEventArgs e)
 158                 {
 159                         user_async_state = null;
 160                         worker = null;
 161
 162                         if (cts != null) {
 163                                 cts.Dispose();
 164                                 cts = null;
 165                         }
 166
 167                         if (PingCompleted != null)
 168                                 PingCompleted (this, e);
 169                 }
 170
 171                 // Sync
 172
 173                 public PingReply Send (IPAddress address)
 174                 {
 175                         return Send (address, default_timeout);
 176                 }
 177
 178                 public PingReply Send (IPAddress address, int timeout)
 179                 {
 180                         return Send (address, timeout, default_buffer);
 181                 }
 182
 183                 public PingReply Send (IPAddress address, int timeout, byte [] buffer)
 184                 {
 185                         return Send (address, timeout, buffer, new PingOptions ());
 186                 }
 187
 188                 public PingReply Send (string hostNameOrAddress)
 189                 {
 190                         return Send (hostNameOrAddress, default_timeout);
 191                 }
 192
 193                 public PingReply Send (string hostNameOrAddress, int timeout)
 194                 {
 195                         return Send (hostNameOrAddress, timeout, default_buffer);
 196                 }
 197
 198                 public PingReply Send (string hostNameOrAddress, int timeout, byte [] buffer)
 199                 {
 200                         return Send (hostNameOrAddress, timeout, buffer, new PingOptions ());
 201                 }
 202
 203                 public PingReply Send (string hostNameOrAddress, int timeout, byte [] buffer, PingOptions options)
 204                 {
 205                         IPAddress [] addresses = Dns.GetHostAddresses (hostNameOrAddress);
 206                         return Send (addresses [0], timeout, buffer, options);
 207                 }
 208
 209                 public PingReply Send (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 210                 {
 211                         if (address == null)
 212                                 throw new ArgumentNullException ("address");
 213                         if (timeout < 0)
 214                                 throw new ArgumentOutOfRangeException ("timeout", "timeout must be non-negative integer");
 215                         if (buffer == null)
 216                                 throw new ArgumentNullException ("buffer");
 217                         if (buffer.Length > 65500)
 218                                 throw new ArgumentException ("buffer");
 219                         // options can be null.
 220
 221 #if MONOTOUCH
 222                         throw new InvalidOperationException ();
 223 #else
 224                         if (canSendPrivileged)
 225                                 return SendPrivileged (address, timeout, buffer, options);
 226                         return SendUnprivileged (address, timeout, buffer, options);
 227 #endif
 228                 }
 229
 230 #if !MONOTOUCH
 231                 private PingReply SendPrivileged (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 232                 {
 233                         IPEndPoint target = new IPEndPoint (address, 0);
 234
 235                         // FIXME: support IPv6
 236                         using (Socket s = new Socket (AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp)) {
 237                                 if (options != null) {
 238                                         s.DontFragment = options.DontFragment;
 239                                         s.Ttl = (short) options.Ttl;
 240                                 }
 241                                 s.SendTimeout = timeout;
 242                                 s.ReceiveTimeout = timeout;
 243                                 // not sure why Identifier = 0 is unacceptable ...
 244                                 IcmpMessage send = new IcmpMessage (8, 0, identifier, 0, buffer);
 245                                 byte [] bytes = send.GetBytes ();
 246                                 s.SendBufferSize = bytes.Length;
 247                                 s.SendTo (bytes, bytes.Length, SocketFlags.None, target);
 248
 249                                 var sw = Stopwatch.StartNew ();
 250
 251                                 // receive
 252                                 bytes = new byte [100];
 253                                 do {
 254                                         EndPoint endpoint = target;
 255                                         SocketError error = 0;
 256                                         int rc = s.ReceiveFrom (bytes, 0, 100, SocketFlags.None,
 257                                                         ref endpoint, out error);
 258
 259                                         if (error != SocketError.Success) {
 260                                                 if (error == SocketError.TimedOut) {
 261                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 262                                                 }
 263                                                 throw new NotSupportedException (String.Format ("Unexpected socket error during ping request: {0}", error));
 264                                         }
 265                                         long rtt = (long) sw.ElapsedMilliseconds;
 266                                         int headerLength = (bytes [0] & 0xF) << 2;
 267                                         int bodyLength = rc - headerLength;
 268
 269                                         // Ping reply to different request. discard it.
 270                                         if (!((IPEndPoint) endpoint).Address.Equals (target.Address)) {
 271                                                 long t = timeout - rtt;
 272                                                 if (t <= 0)
 273                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 274                                                 s.ReceiveTimeout = (int) t;
 275                                                 continue;
 276                                         }
 277
 278                                         IcmpMessage recv = new IcmpMessage (bytes, headerLength, bodyLength);
 279
 280                                         /* discard ping reply to different request or echo requests if running on same host. */
 281                                         if (recv.Identifier != identifier || recv.Type == 8) {
 282                                                 long t = timeout - rtt;
 283                                                 if (t <= 0)
 284                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 285                                                 s.ReceiveTimeout = (int) t;
 286                                                 continue;
 287                                         }
 288
 289                                         return new PingReply (address, recv.Data, options, rtt, recv.IPStatus);
 290                                 } while (true);
 291                         }
 292                 }
 293
 294                 private PingReply SendUnprivileged (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 295                 {
 296 #if MONO_FEATURE_PROCESS_START
 297                         var sw = Stopwatch.StartNew ();
 298
 299                         Process ping = new Process ();
 300                         string args = BuildPingArgs (address, timeout, options);
 301                         long trip_time = 0;
 302
 303                         ping.StartInfo.FileName = PingBinPath;
 304                         ping.StartInfo.Arguments = args;
 305
 306                         ping.StartInfo.CreateNoWindow = true;
 307                         ping.StartInfo.UseShellExecute = false;
 308
 309                         ping.StartInfo.RedirectStandardOutput = true;
 310                         ping.StartInfo.RedirectStandardError = true;
 311
 312                         IPStatus status = IPStatus.Unknown;
 313                         try {
 314                                 ping.Start ();
 315
 316 #pragma warning disable 219
 317                                 string stdout = ping.StandardOutput.ReadToEnd ();
 318                                 string stderr = ping.StandardError.ReadToEnd ();
 319 #pragma warning restore 219
 320
 321                                 trip_time = (long) sw.ElapsedMilliseconds;
 322                                 if (!ping.WaitForExit (timeout) || (ping.HasExited && ping.ExitCode == 2))
 323                                         status = IPStatus.TimedOut;
 324                                 else if (ping.ExitCode == 0)
 325                                         status = IPStatus.Success;
 326                                 else if (ping.ExitCode == 1)
 327                                         status = IPStatus.TtlExpired;
 328                         } catch {
 329                         } finally {
 330                                 if (!ping.HasExited)
 331                                         ping.Kill ();
 332                                 ping.Dispose ();
 333                         }
 334
 335                         return new PingReply (address, buffer, options, trip_time, status);
 336 #else
 337                         throw new PlatformNotSupportedException ("Ping is not supported on this platform.");
 338 #endif // MONO_FEATURE_PROCESS_START
 339                 }
 340 #endif // !MONOTOUCH
 341
 342                 // Async
 343
 344                 public void SendAsync (IPAddress address, int timeout, byte [] buffer, object userToken)
 345                 {
 346                         SendAsync (address, default_timeout, default_buffer, new PingOptions (), userToken);
 347                 }
 348
 349                 public void SendAsync (IPAddress address, int timeout, object userToken)
 350                 {
 351                         SendAsync (address, default_timeout, default_buffer, userToken);
 352                 }
 353
 354                 public void SendAsync (IPAddress address, object userToken)
 355                 {
 356                         SendAsync (address, default_timeout, userToken);
 357                 }
 358
 359                 public void SendAsync (string hostNameOrAddress, int timeout, byte [] buffer, object userToken)
 360                 {
 361                         SendAsync (hostNameOrAddress, timeout, buffer, new PingOptions (), userToken);
 362                 }
 363
 364                 public void SendAsync (string hostNameOrAddress, int timeout, byte [] buffer, PingOptions options, object userToken)
 365                 {
 366                         IPAddress address = Dns.GetHostEntry (hostNameOrAddress).AddressList [0];
 367                         SendAsync (address, timeout, buffer, options, userToken);
 368                 }
 369
 370                 public void SendAsync (string hostNameOrAddress, int timeout, object userToken)
 371                 {
 372                         SendAsync (hostNameOrAddress, timeout, default_buffer, userToken);
 373                 }
 374
 375                 public void SendAsync (string hostNameOrAddress, object userToken)
 376                 {
 377                         SendAsync (hostNameOrAddress, default_timeout, userToken);
 378                 }
 379
 380                 public void SendAsync (IPAddress address, int timeout, byte [] buffer, PingOptions options, object userToken)
 381                 {
 382                         if ((worker != null) || (cts != null))
 383                                 throw new InvalidOperationException ("Another SendAsync operation is in progress");
 384
 385                         worker = new BackgroundWorker ();
 386                         worker.DoWork += delegate (object o, DoWorkEventArgs ea) {
 387                                 try {
 388                                         user_async_state = ea.Argument;
 389                                         ea.Result = Send (address, timeout, buffer, options);
 390                                 } catch (Exception ex) {
 391                                         ea.Result = ex;
 392                                 }
 393                         };
 394                         worker.WorkerSupportsCancellation = true;
 395                         worker.RunWorkerCompleted += delegate (object o, RunWorkerCompletedEventArgs ea) {
 396                                 // Note that RunWorkerCompletedEventArgs.UserState cannot be used (LAMESPEC)
 397                                 OnPingCompleted (new PingCompletedEventArgs (ea.Error, ea.Cancelled, user_async_state, ea.Result as PingReply));
 398                         };
 399                         worker.RunWorkerAsync (userToken);
 400                 }
 401
 402                 // SendAsyncCancel
 403
 404                 public void SendAsyncCancel ()
 405                 {
 406                         if (cts != null) {
 407                                 cts.Cancel ();
 408                                 return;
 409                         }
 410
 411                         if (worker == null)
 412                                 throw new InvalidOperationException ("SendAsync operation is not in progress");
 413                         worker.CancelAsync ();
 414                 }
 415
 416 #if !MONOTOUCH
 417                 // ICMP message
 418
 419                 class IcmpMessage
 420                 {
 421                         byte [] bytes;
 422
 423                         // received
 424                         public IcmpMessage (byte [] bytes, int offset, int size)
 425                         {
 426                                 this.bytes = new byte [size];
 427                                 Buffer.BlockCopy (bytes, offset, this.bytes, 0, size);
 428                         }
 429
 430                         // to be sent
 431                         public IcmpMessage (byte type, byte code, ushort identifier, ushort sequence, byte [] data)
 432                         {
 433                                 bytes = new byte [data.Length + 8];
 434                                 bytes [0] = type;
 435                                 bytes [1] = code;
 436                                 bytes [4] = (byte) (identifier & 0xFF);
 437                                 bytes [5] = (byte) ((int) identifier >> 8);
 438                                 bytes [6] = (byte) (sequence & 0xFF);
 439                                 bytes [7] = (byte) ((int) sequence >> 8);
 440                                 Buffer.BlockCopy (data, 0, bytes, 8, data.Length);
 441
 442                                 ushort checksum = ComputeChecksum (bytes);
 443                                 bytes [2] = (byte) (checksum & 0xFF);
 444                                 bytes [3] = (byte) ((int) checksum >> 8);
 445                         }
 446
 447                         public byte Type {
 448                                 get { return bytes [0]; }
 449                         }
 450
 451                         public byte Code {
 452                                 get { return bytes [1]; }
 453                         }
 454
 455                         public ushort Identifier {
 456                                 get { return (ushort) (bytes [4] + (bytes [5] << 8)); }
 457                         }
 458
 459                         public ushort Sequence {
 460                                 get { return (ushort) (bytes [6] + (bytes [7] << 8)); }
 461                         }
 462
 463                         public byte [] Data {
 464                                 get {
 465                                         byte [] data = new byte [bytes.Length - 8];
 466                                         Buffer.BlockCopy (bytes, 8, data, 0, data.Length);
 467                                         return data;
 468                                 }
 469                         }
 470
 471                         public byte [] GetBytes ()
 472                         {
 473                                 return bytes;
 474                         }
 475
 476                         static ushort ComputeChecksum (byte [] data)
 477                         {
 478                                 uint ret = 0;
 479                                 for (int i = 0; i < data.Length; i += 2) {
 480                                         ushort us = i + 1 < data.Length ? data [i + 1] : (byte) 0;
 481                                         us <<= 8;
 482                                         us += data [i];
 483                                         ret += us;
 484                                 }
 485                                 ret = (ret >> 16) + (ret & 0xFFFF);
 486                                 return (ushort) ~ ret;
 487                         }
 488
 489                         public IPStatus IPStatus {
 490                                 get {
 491                                         switch (Type) {
 492                                         case 0:
 493                                                 return IPStatus.Success;
 494                                         case 3: // destination unreacheable
 495                                                 switch (Code) {
 496                                                 case 0:
 497                                                         return IPStatus.DestinationNetworkUnreachable;
 498                                                 case 1:
 499                                                         return IPStatus.DestinationHostUnreachable;
 500                                                 case 2:
 501                                                         return IPStatus.DestinationProtocolUnreachable;
 502                                                 case 3:
 503                                                         return IPStatus.DestinationPortUnreachable;
 504                                                 case 4:
 505                                                         return IPStatus.BadOption; // FIXME: likely wrong
 506                                                 case 5:
 507                                                         return IPStatus.BadRoute; // not sure if it is correct
 508                                                 }
 509                                                 break;
 510                                         case 11:
 511                                                 switch (Code) {
 512                                                 case 0:
 513                                                         return IPStatus.TimeExceeded;
 514                                                 case 1:
 515                                                         return IPStatus.TtlReassemblyTimeExceeded;
 516                                                 }
 517                                                 break;
 518                                         case 12:
 519                                                 return IPStatus.ParameterProblem;
 520                                         case 4:
 521                                                 return IPStatus.SourceQuench;
 522                                         case 8:
 523                                                 return IPStatus.Success;
 524                                         }
 525                                         return IPStatus.Unknown;
 526                                         //throw new NotSupportedException (String.Format ("Unexpected pair of ICMP message type and code: type is {0} and code is {1}", Type, Code));
 527                                 }
 528                         }
 529                 }
 530
 531                 private string BuildPingArgs (IPAddress address, int timeout, PingOptions options)
 532                 {
 533                         CultureInfo culture = CultureInfo.InvariantCulture;
 534                         StringBuilder args = new StringBuilder ();
 535                         uint t = Convert.ToUInt32 (Math.Floor ((timeout + 1000) / 1000.0));
 536                         bool is_mac = Platform.IsMacOS;
 537                         if (!is_mac)
 538                                 args.AppendFormat (culture, "-q -n -c {0} -w {1} -t {2} -M ", DefaultCount, t, options.Ttl);
 539                         else
 540                                 args.AppendFormat (culture, "-q -n -c {0} -t {1} -o -m {2} ", DefaultCount, t, options.Ttl);
 541                         if (!is_mac)
 542                                 args.Append (options.DontFragment ? "do " : "dont ");
 543                         else if (options.DontFragment)
 544                                 args.Append ("-D ");
 545
 546                         args.Append (address.ToString ());
 547
 548                         return args.ToString ();
 549                 }
 550 #endif // !MONOTOUCH
 551
 552                 public Task<PingReply> SendPingAsync (IPAddress address, int timeout, byte [] buffer)
 553                 {
 554                         return SendPingAsync (address, default_timeout, default_buffer, new PingOptions ());
 555                 }
 556
 557                 public Task<PingReply> SendPingAsync (IPAddress address, int timeout)
 558                 {
 559                         return SendPingAsync (address, default_timeout, default_buffer);
 560                 }
 561
 562                 public Task<PingReply> SendPingAsync (IPAddress address)
 563                 {
 564                         return SendPingAsync (address, default_timeout);
 565                 }
 566
 567                 public Task<PingReply> SendPingAsync (string hostNameOrAddress, int timeout, byte [] buffer)
 568                 {
 569                         return SendPingAsync (hostNameOrAddress, timeout, buffer, new PingOptions ());
 570                 }
 571
 572                 public Task<PingReply> SendPingAsync (string hostNameOrAddress, int timeout, byte [] buffer, PingOptions options)
 573                 {
 574                         IPAddress address = Dns.GetHostEntry (hostNameOrAddress).AddressList [0];
 575                         return SendPingAsync (address, timeout, buffer, options);
 576                 }
 577
 578                 public Task<PingReply> SendPingAsync (string hostNameOrAddress, int timeout)
 579                 {
 580                         return SendPingAsync (hostNameOrAddress, timeout, default_buffer);
 581                 }
 582
 583                 public Task<PingReply> SendPingAsync (string hostNameOrAddress)
 584                 {
 585                         return SendPingAsync (hostNameOrAddress, default_timeout);
 586                 }
 587
 588                 public Task<PingReply> SendPingAsync (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 589                 {
 590                         if ((worker != null) || (cts != null))
 591                                 throw new InvalidOperationException ("Another SendAsync operation is in progress");
 592
 593                         cts = new CancellationTokenSource();
 594
 595                         var task = Task<PingReply>.Factory.StartNew (
 596                                 () => Send (address, timeout, buffer, options), cts.Token);
 597
 598                         task.ContinueWith ((t) => {
 599                                 if (t.IsCanceled)
 600                                         OnPingCompleted (new PingCompletedEventArgs (null, true, null, null));
 601                                 else if (t.IsFaulted)
 602                                         OnPingCompleted (new PingCompletedEventArgs (t.Exception, false, null, null));
 603                                 else
 604                                         OnPingCompleted (new PingCompletedEventArgs (null, false, null, t.Result));
 605                         });
 606
 607                         return task;
 608                 }
 609         }
 610 }