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 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 using System;
  31 using System.IO;
  32 using System.Text;
  33 using System.Diagnostics;
  34 using System.Globalization;
  35 using System.ComponentModel;
  36 using System.Net.Sockets;
  37 using System.Security.Principal;
  38 using System.Security.Cryptography;
  39 using System.Runtime.InteropServices;
  40 using System.Threading;
  41 using System.Threading.Tasks;
  42
  43 namespace System.Net.NetworkInformation {
  44         [MonoTODO ("IPv6 support is missing")]
  45         public class Ping : Component, IDisposable
  46         {
  47                 [StructLayout(LayoutKind.Sequential)]
  48                 struct cap_user_header_t
  49                 {
  50                         public UInt32 version;
  51                         public Int32 pid;
  52                 };
  53
  54                 [StructLayout(LayoutKind.Sequential)]
  55                 struct cap_user_data_t
  56                 {
  57                         public UInt32 effective;
  58                         public UInt32 permitted;
  59                         public UInt32 inheritable;
  60                 }
  61
  62                 const int DefaultCount = 1;
  63                 static readonly string [] PingBinPaths = new string [] {
  64                         "/bin/ping",
  65                         "/sbin/ping",
  66                         "/usr/sbin/ping",
  67 #if MONODROID
  68                         "/system/bin/ping"
  69 #endif
  70                 };
  71                 static readonly string PingBinPath;
  72                 const int default_timeout = 4000; // 4 sec.
  73                 ushort identifier;
  74
  75                 // This value is correct as of Linux kernel version 2.6.25.9
  76                 // See /usr/include/linux/capability.h
  77                 const UInt32 linux_cap_version = 0x20071026;
  78
  79                 static readonly byte [] default_buffer = new byte [0];
  80                 static bool canSendPrivileged;
  81
  82
  83                 BackgroundWorker worker;
  84                 object user_async_state;
  85                 CancellationTokenSource cts;
  86
  87                 public event PingCompletedEventHandler PingCompleted;
  88
  89                 static Ping ()
  90                 {
  91                         if (Environment.OSVersion.Platform == PlatformID.Unix) {
  92                                 CheckLinuxCapabilities ();
  93                                 if (!canSendPrivileged && WindowsIdentity.GetCurrent ().Name == "root")
  94                                         canSendPrivileged = true;
  95
  96                                 // Since different Unix systems can have different path to bin, we try some
  97                                 // of the known ones.
  98                                 foreach (string ping_path in PingBinPaths)
  99                                         if (File.Exists (ping_path)) {
 100                                                 PingBinPath = ping_path;
 101                                                 break;
 102                                         }
 103                         }
 104                         else
 105                                 canSendPrivileged = true;
 106
 107                         if (PingBinPath == null)
 108                                 PingBinPath = "/bin/ping"; // default, fallback value
 109                 }
 110
 111                 public Ping ()
 112                 {
 113                         // Generate a new random 16 bit identifier for every ping
 114                         RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider ();
 115                         byte [] randomIdentifier = new byte [2];
 116                         rng.GetBytes (randomIdentifier);
 117                         identifier = (ushort)(randomIdentifier [0] + (randomIdentifier [1] << 8));
 118                 }
 119
 120                 [DllImport ("libc", EntryPoint="capget")]
 121                 static extern int capget (ref cap_user_header_t header, ref cap_user_data_t data);
 122
 123                 static void CheckLinuxCapabilities ()
 124                 {
 125                         try {
 126                                 cap_user_header_t header = new cap_user_header_t ();
 127                                 cap_user_data_t data = new cap_user_data_t ();
 128
 129                                 header.version = linux_cap_version;
 130
 131                                 int ret = -1;
 132
 133                                 try {
 134                                         ret = capget (ref header, ref data);
 135                                 } catch (Exception) {
 136                                 }
 137
 138                                 if (ret == -1)
 139                                         return;
 140
 141                                 canSendPrivileged = (data.effective & (1 << 13)) != 0;
 142                         } catch {
 143                                 canSendPrivileged = false;
 144                         }
 145                 }
 146
 147                 void IDisposable.Dispose ()
 148                 {
 149                 }
 150
 151                 protected void OnPingCompleted (PingCompletedEventArgs e)
 152                 {
 153                         user_async_state = null;
 154                         worker = null;
 155                         cts = null;
 156
 157                         if (PingCompleted != null)
 158                                 PingCompleted (this, e);
 159                 }
 160
 161                 // Sync
 162
 163                 public PingReply Send (IPAddress address)
 164                 {
 165                         return Send (address, default_timeout);
 166                 }
 167
 168                 public PingReply Send (IPAddress address, int timeout)
 169                 {
 170                         return Send (address, timeout, default_buffer);
 171                 }
 172
 173                 public PingReply Send (IPAddress address, int timeout, byte [] buffer)
 174                 {
 175                         return Send (address, timeout, buffer, new PingOptions ());
 176                 }
 177
 178                 public PingReply Send (string hostNameOrAddress)
 179                 {
 180                         return Send (hostNameOrAddress, default_timeout);
 181                 }
 182
 183                 public PingReply Send (string hostNameOrAddress, int timeout)
 184                 {
 185                         return Send (hostNameOrAddress, timeout, default_buffer);
 186                 }
 187
 188                 public PingReply Send (string hostNameOrAddress, int timeout, byte [] buffer)
 189                 {
 190                         return Send (hostNameOrAddress, timeout, buffer, new PingOptions ());
 191                 }
 192
 193                 public PingReply Send (string hostNameOrAddress, int timeout, byte [] buffer, PingOptions options)
 194                 {
 195                         IPAddress [] addresses = Dns.GetHostAddresses (hostNameOrAddress);
 196                         return Send (addresses [0], timeout, buffer, options);
 197                 }
 198
 199                 static IPAddress GetNonLoopbackIP ()
 200                 {
 201                         foreach (IPAddress addr in Dns.GetHostByName (Dns.GetHostName ()).AddressList)
 202                                 if (!IPAddress.IsLoopback (addr))
 203                                         return addr;
 204                         throw new InvalidOperationException ("Could not resolve non-loopback IP address for localhost");
 205                 }
 206
 207                 public PingReply Send (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 208                 {
 209                         if (address == null)
 210                                 throw new ArgumentNullException ("address");
 211                         if (timeout < 0)
 212                                 throw new ArgumentOutOfRangeException ("timeout", "timeout must be non-negative integer");
 213                         if (buffer == null)
 214                                 throw new ArgumentNullException ("buffer");
 215                         if (buffer.Length > 65500)
 216                                 throw new ArgumentException ("buffer");
 217                         // options can be null.
 218
 219                         if (canSendPrivileged)
 220                                 return SendPrivileged (address, timeout, buffer, options);
 221                         return SendUnprivileged (address, timeout, buffer, options);
 222                 }
 223
 224                 private PingReply SendPrivileged (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 225                 {
 226                         IPEndPoint target = new IPEndPoint (address, 0);
 227                         IPEndPoint client = new IPEndPoint (GetNonLoopbackIP (), 0);
 228
 229                         // FIXME: support IPv6
 230                         using (Socket s = new Socket (AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp)) {
 231                                 if (options != null) {
 232                                         s.DontFragment = options.DontFragment;
 233                                         s.Ttl = (short) options.Ttl;
 234                                 }
 235                                 s.SendTimeout = timeout;
 236                                 s.ReceiveTimeout = timeout;
 237                                 // not sure why Identifier = 0 is unacceptable ...
 238                                 IcmpMessage send = new IcmpMessage (8, 0, identifier, 0, buffer);
 239                                 byte [] bytes = send.GetBytes ();
 240                                 s.SendBufferSize = bytes.Length;
 241                                 s.SendTo (bytes, bytes.Length, SocketFlags.None, target);
 242
 243                                 DateTime sentTime = DateTime.Now;
 244
 245                                 // receive
 246                                 bytes = new byte [100];
 247                                 do {
 248                                         EndPoint endpoint = client;
 249                                         int error = 0;
 250                                         int rc = s.ReceiveFrom_nochecks_exc (bytes, 0, 100, SocketFlags.None,
 251                                                         ref endpoint, false, out error);
 252
 253                                         if (error != 0) {
 254                                                 if (error == (int) SocketError.TimedOut) {
 255                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 256                                                 }
 257                                                 throw new NotSupportedException (String.Format ("Unexpected socket error during ping request: {0}", error));
 258                                         }
 259                                         long rtt = (long) (DateTime.Now - sentTime).TotalMilliseconds;
 260                                         int headerLength = (bytes [0] & 0xF) << 2;
 261                                         int bodyLength = rc - headerLength;
 262
 263                                         // Ping reply to different request. discard it.
 264                                         if (!((IPEndPoint) endpoint).Address.Equals (target.Address)) {
 265                                                 long t = timeout - rtt;
 266                                                 if (t <= 0)
 267                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 268                                                 s.ReceiveTimeout = (int) t;
 269                                                 continue;
 270                                         }
 271
 272                                         IcmpMessage recv = new IcmpMessage (bytes, headerLength, bodyLength);
 273
 274                                         /* discard ping reply to different request or echo requests if running on same host. */
 275                                         if (recv.Identifier != identifier || recv.Type == 8) {
 276                                                 long t = timeout - rtt;
 277                                                 if (t <= 0)
 278                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 279                                                 s.ReceiveTimeout = (int) t;
 280                                                 continue;
 281                                         }
 282
 283                                         return new PingReply (address, recv.Data, options, rtt, recv.IPStatus);
 284                                 } while (true);
 285                         }
 286                 }
 287
 288                 private PingReply SendUnprivileged (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 289                 {
 290 #if MONO_FEATURE_PROCESS_START
 291                         DateTime sentTime = DateTime.UtcNow;
 292
 293                         Process ping = new Process ();
 294                         string args = BuildPingArgs (address, timeout, options);
 295                         long trip_time = 0;
 296
 297                         ping.StartInfo.FileName = PingBinPath;
 298                         ping.StartInfo.Arguments = args;
 299
 300                         ping.StartInfo.CreateNoWindow = true;
 301                         ping.StartInfo.UseShellExecute = false;
 302
 303                         ping.StartInfo.RedirectStandardOutput = true;
 304                         ping.StartInfo.RedirectStandardError = true;
 305
 306                         IPStatus status = IPStatus.Unknown;
 307                         try {
 308                                 ping.Start ();
 309
 310 #pragma warning disable 219
 311                                 string stdout = ping.StandardOutput.ReadToEnd ();
 312                                 string stderr = ping.StandardError.ReadToEnd ();
 313 #pragma warning restore 219
 314
 315                                 trip_time = (long) (DateTime.UtcNow - sentTime).TotalMilliseconds;
 316                                 if (!ping.WaitForExit (timeout) || (ping.HasExited && ping.ExitCode == 2))
 317                                         status = IPStatus.TimedOut;
 318                                 else if (ping.ExitCode == 0)
 319                                         status = IPStatus.Success;
 320                                 else if (ping.ExitCode == 1)
 321                                         status = IPStatus.TtlExpired;
 322                         } catch {
 323                         } finally {
 324                                 if (!ping.HasExited)
 325                                         ping.Kill ();
 326                                 ping.Dispose ();
 327                         }
 328
 329                         return new PingReply (address, buffer, options, trip_time, status);
 330 #else
 331                         throw new NotSupportedException ("Ping is not supported on this platform.");
 332 #endif // MONO_FEATURE_PROCESS_START
 333                 }
 334
 335                 // Async
 336
 337                 public void SendAsync (IPAddress address, int timeout, byte [] buffer, object userToken)
 338                 {
 339                         SendAsync (address, default_timeout, default_buffer, new PingOptions (), userToken);
 340                 }
 341
 342                 public void SendAsync (IPAddress address, int timeout, object userToken)
 343                 {
 344                         SendAsync (address, default_timeout, default_buffer, userToken);
 345                 }
 346
 347                 public void SendAsync (IPAddress address, object userToken)
 348                 {
 349                         SendAsync (address, default_timeout, userToken);
 350                 }
 351
 352                 public void SendAsync (string hostNameOrAddress, int timeout, byte [] buffer, object userToken)
 353                 {
 354                         SendAsync (hostNameOrAddress, timeout, buffer, new PingOptions (), userToken);
 355                 }
 356
 357                 public void SendAsync (string hostNameOrAddress, int timeout, byte [] buffer, PingOptions options, object userToken)
 358                 {
 359                         IPAddress address = Dns.GetHostEntry (hostNameOrAddress).AddressList [0];
 360                         SendAsync (address, timeout, buffer, options, userToken);
 361                 }
 362
 363                 public void SendAsync (string hostNameOrAddress, int timeout, object userToken)
 364                 {
 365                         SendAsync (hostNameOrAddress, timeout, default_buffer, userToken);
 366                 }
 367
 368                 public void SendAsync (string hostNameOrAddress, object userToken)
 369                 {
 370                         SendAsync (hostNameOrAddress, default_timeout, userToken);
 371                 }
 372
 373                 public void SendAsync (IPAddress address, int timeout, byte [] buffer, PingOptions options, object userToken)
 374                 {
 375                         if ((worker != null) || (cts != null))
 376                                 throw new InvalidOperationException ("Another SendAsync operation is in progress");
 377
 378                         worker = new BackgroundWorker ();
 379                         worker.DoWork += delegate (object o, DoWorkEventArgs ea) {
 380                                 try {
 381                                         user_async_state = ea.Argument;
 382                                         ea.Result = Send (address, timeout, buffer, options);
 383                                 } catch (Exception ex) {
 384                                         ea.Result = ex;
 385                                 }
 386                         };
 387                         worker.WorkerSupportsCancellation = true;
 388                         worker.RunWorkerCompleted += delegate (object o, RunWorkerCompletedEventArgs ea) {
 389                                 // Note that RunWorkerCompletedEventArgs.UserState cannot be used (LAMESPEC)
 390                                 OnPingCompleted (new PingCompletedEventArgs (ea.Error, ea.Cancelled, user_async_state, ea.Result as PingReply));
 391                         };
 392                         worker.RunWorkerAsync (userToken);
 393                 }
 394
 395                 // SendAsyncCancel
 396
 397                 public void SendAsyncCancel ()
 398                 {
 399                         if (cts != null) {
 400                                 cts.Cancel ();
 401                                 return;
 402                         }
 403
 404                         if (worker == null)
 405                                 throw new InvalidOperationException ("SendAsync operation is not in progress");
 406                         worker.CancelAsync ();
 407                 }
 408
 409                 // ICMP message
 410
 411                 class IcmpMessage
 412                 {
 413                         byte [] bytes;
 414
 415                         // received
 416                         public IcmpMessage (byte [] bytes, int offset, int size)
 417                         {
 418                                 this.bytes = new byte [size];
 419                                 Buffer.BlockCopy (bytes, offset, this.bytes, 0, size);
 420                         }
 421
 422                         // to be sent
 423                         public IcmpMessage (byte type, byte code, ushort identifier, ushort sequence, byte [] data)
 424                         {
 425                                 bytes = new byte [data.Length + 8];
 426                                 bytes [0] = type;
 427                                 bytes [1] = code;
 428                                 bytes [4] = (byte) (identifier & 0xFF);
 429                                 bytes [5] = (byte) ((int) identifier >> 8);
 430                                 bytes [6] = (byte) (sequence & 0xFF);
 431                                 bytes [7] = (byte) ((int) sequence >> 8);
 432                                 Buffer.BlockCopy (data, 0, bytes, 8, data.Length);
 433
 434                                 ushort checksum = ComputeChecksum (bytes);
 435                                 bytes [2] = (byte) (checksum & 0xFF);
 436                                 bytes [3] = (byte) ((int) checksum >> 8);
 437                         }
 438
 439                         public byte Type {
 440                                 get { return bytes [0]; }
 441                         }
 442
 443                         public byte Code {
 444                                 get { return bytes [1]; }
 445                         }
 446
 447                         public ushort Identifier {
 448                                 get { return (ushort) (bytes [4] + (bytes [5] << 8)); }
 449                         }
 450
 451                         public ushort Sequence {
 452                                 get { return (ushort) (bytes [6] + (bytes [7] << 8)); }
 453                         }
 454
 455                         public byte [] Data {
 456                                 get {
 457                                         byte [] data = new byte [bytes.Length - 8];
 458                                         Buffer.BlockCopy (bytes, 8, data, 0, data.Length);
 459                                         return data;
 460                                 }
 461                         }
 462
 463                         public byte [] GetBytes ()
 464                         {
 465                                 return bytes;
 466                         }
 467
 468                         static ushort ComputeChecksum (byte [] data)
 469                         {
 470                                 uint ret = 0;
 471                                 for (int i = 0; i < data.Length; i += 2) {
 472                                         ushort us = i + 1 < data.Length ? data [i + 1] : (byte) 0;
 473                                         us <<= 8;
 474                                         us += data [i];
 475                                         ret += us;
 476                                 }
 477                                 ret = (ret >> 16) + (ret & 0xFFFF);
 478                                 return (ushort) ~ ret;
 479                         }
 480
 481                         public IPStatus IPStatus {
 482                                 get {
 483                                         switch (Type) {
 484                                         case 0:
 485                                                 return IPStatus.Success;
 486                                         case 3: // destination unreacheable
 487                                                 switch (Code) {
 488                                                 case 0:
 489                                                         return IPStatus.DestinationNetworkUnreachable;
 490                                                 case 1:
 491                                                         return IPStatus.DestinationHostUnreachable;
 492                                                 case 2:
 493                                                         return IPStatus.DestinationProtocolUnreachable;
 494                                                 case 3:
 495                                                         return IPStatus.DestinationPortUnreachable;
 496                                                 case 4:
 497                                                         return IPStatus.BadOption; // FIXME: likely wrong
 498                                                 case 5:
 499                                                         return IPStatus.BadRoute; // not sure if it is correct
 500                                                 }
 501                                                 break;
 502                                         case 11:
 503                                                 switch (Code) {
 504                                                 case 0:
 505                                                         return IPStatus.TimeExceeded;
 506                                                 case 1:
 507                                                         return IPStatus.TtlReassemblyTimeExceeded;
 508                                                 }
 509                                                 break;
 510                                         case 12:
 511                                                 return IPStatus.ParameterProblem;
 512                                         case 4:
 513                                                 return IPStatus.SourceQuench;
 514                                         case 8:
 515                                                 return IPStatus.Success;
 516                                         }
 517                                         return IPStatus.Unknown;
 518                                         //throw new NotSupportedException (String.Format ("Unexpected pair of ICMP message type and code: type is {0} and code is {1}", Type, Code));
 519                                 }
 520                         }
 521                 }
 522
 523                 private string BuildPingArgs (IPAddress address, int timeout, PingOptions options)
 524                 {
 525                         CultureInfo culture = CultureInfo.InvariantCulture;
 526                         StringBuilder args = new StringBuilder ();
 527                         uint t = Convert.ToUInt32 (Math.Floor ((timeout + 1000) / 1000.0));
 528                         bool is_mac = Platform.IsMacOS;
 529                         if (!is_mac)
 530                                 args.AppendFormat (culture, "-q -n -c {0} -w {1} -t {2} -M ", DefaultCount, t, options.Ttl);
 531                         else
 532                                 args.AppendFormat (culture, "-q -n -c {0} -t {1} -o -m {2} ", DefaultCount, t, options.Ttl);
 533                         if (!is_mac)
 534                                 args.Append (options.DontFragment ? "do " : "dont ");
 535                         else if (options.DontFragment)
 536                                 args.Append ("-D ");
 537
 538                         args.Append (address.ToString ());
 539
 540                         return args.ToString ();
 541                 }
 542
 543                 public Task<PingReply> SendPingAsync (IPAddress address, int timeout, byte [] buffer)
 544                 {
 545                         return SendPingAsync (address, default_timeout, default_buffer, new PingOptions ());
 546                 }
 547
 548                 public Task<PingReply> SendPingAsync (IPAddress address, int timeout)
 549                 {
 550                         return SendPingAsync (address, default_timeout, default_buffer);
 551                 }
 552
 553                 public Task<PingReply> SendPingAsync (IPAddress address)
 554                 {
 555                         return SendPingAsync (address, default_timeout);
 556                 }
 557
 558                 public Task<PingReply> SendPingAsync (string hostNameOrAddress, int timeout, byte [] buffer)
 559                 {
 560                         return SendPingAsync (hostNameOrAddress, timeout, buffer, new PingOptions ());
 561                 }
 562
 563                 public Task<PingReply> SendPingAsync (string hostNameOrAddress, int timeout, byte [] buffer, PingOptions options)
 564                 {
 565                         IPAddress address = Dns.GetHostEntry (hostNameOrAddress).AddressList [0];
 566                         return SendPingAsync (address, timeout, buffer, options);
 567                 }
 568
 569                 public Task<PingReply> SendPingAsync (string hostNameOrAddress, int timeout)
 570                 {
 571                         return SendPingAsync (hostNameOrAddress, timeout, default_buffer);
 572                 }
 573
 574                 public Task<PingReply> SendPingAsync (string hostNameOrAddress)
 575                 {
 576                         return SendPingAsync (hostNameOrAddress, default_timeout);
 577                 }
 578
 579                 public Task<PingReply> SendPingAsync (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 580                 {
 581                         if ((worker != null) || (cts != null))
 582                                 throw new InvalidOperationException ("Another SendAsync operation is in progress");
 583
 584                         var task = Task<PingReply>.Factory.StartNew (
 585                                 () => Send (address, timeout, buffer, options), cts.Token);
 586
 587                         task.ContinueWith ((t) => {
 588                                 if (t.IsCanceled)
 589                                         OnPingCompleted (new PingCompletedEventArgs (null, true, null, null));
 590                                 else if (t.IsFaulted)
 591                                         OnPingCompleted (new PingCompletedEventArgs (t.Exception, false, null, null));
 592                                 else
 593                                         OnPingCompleted (new PingCompletedEventArgs (null, false, null, t.Result));
 594                         });
 595
 596                         return task;
 597                 }
 598         }
 599 }