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