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 #if NET_4_5
  40 using System.Threading;
  41 using System.Threading.Tasks;
  42 #endif
  43
  44 namespace System.Net.NetworkInformation {
  45         [MonoTODO ("IPv6 support is missing")]
  46         public class Ping : Component, IDisposable
  47         {
  48                 [StructLayout(LayoutKind.Sequential)]
  49                 struct cap_user_header_t
  50                 {
  51                         public UInt32 version;
  52                         public Int32 pid;
  53                 };
  54
  55                 [StructLayout(LayoutKind.Sequential)]
  56                 struct cap_user_data_t
  57                 {
  58                         public UInt32 effective;
  59                         public UInt32 permitted;
  60                         public UInt32 inheritable;
  61                 }
  62
  63                 const int DefaultCount = 1;
  64                 static readonly string [] PingBinPaths = new string [] {
  65                         "/bin/ping",
  66                         "/sbin/ping",
  67                         "/usr/sbin/ping"
  68                 };
  69                 static readonly string PingBinPath;
  70                 const int default_timeout = 4000; // 4 sec.
  71                 ushort identifier;
  72
  73                 // This value is correct as of Linux kernel version 2.6.25.9
  74                 // See /usr/include/linux/capability.h
  75                 const UInt32 linux_cap_version = 0x20071026;
  76
  77                 static readonly byte [] default_buffer = new byte [0];
  78                 static bool canSendPrivileged;
  79
  80
  81                 BackgroundWorker worker;
  82                 object user_async_state;
  83 #if NET_4_5
  84                 CancellationTokenSource cts;
  85 #endif
  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 #if NET_4_5
 156                         cts = null;
 157 #endif
 158
 159                         if (PingCompleted != null)
 160                                 PingCompleted (this, e);
 161                 }
 162
 163                 // Sync
 164
 165                 public PingReply Send (IPAddress address)
 166                 {
 167                         return Send (address, default_timeout);
 168                 }
 169
 170                 public PingReply Send (IPAddress address, int timeout)
 171                 {
 172                         return Send (address, timeout, default_buffer);
 173                 }
 174
 175                 public PingReply Send (IPAddress address, int timeout, byte [] buffer)
 176                 {
 177                         return Send (address, timeout, buffer, new PingOptions ());
 178                 }
 179
 180                 public PingReply Send (string hostNameOrAddress)
 181                 {
 182                         return Send (hostNameOrAddress, default_timeout);
 183                 }
 184
 185                 public PingReply Send (string hostNameOrAddress, int timeout)
 186                 {
 187                         return Send (hostNameOrAddress, timeout, default_buffer);
 188                 }
 189
 190                 public PingReply Send (string hostNameOrAddress, int timeout, byte [] buffer)
 191                 {
 192                         return Send (hostNameOrAddress, timeout, buffer, new PingOptions ());
 193                 }
 194
 195                 public PingReply Send (string hostNameOrAddress, int timeout, byte [] buffer, PingOptions options)
 196                 {
 197                         IPAddress [] addresses = Dns.GetHostAddresses (hostNameOrAddress);
 198                         return Send (addresses [0], timeout, buffer, options);
 199                 }
 200
 201                 static IPAddress GetNonLoopbackIP ()
 202                 {
 203                         foreach (IPAddress addr in Dns.GetHostByName (Dns.GetHostName ()).AddressList)
 204                                 if (!IPAddress.IsLoopback (addr))
 205                                         return addr;
 206                         throw new InvalidOperationException ("Could not resolve non-loopback IP address for localhost");
 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 (canSendPrivileged)
 222                                 return SendPrivileged (address, timeout, buffer, options);
 223                         return SendUnprivileged (address, timeout, buffer, options);
 224                 }
 225
 226                 private PingReply SendPrivileged (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 227                 {
 228                         IPEndPoint target = new IPEndPoint (address, 0);
 229                         IPEndPoint client = new IPEndPoint (GetNonLoopbackIP (), 0);
 230
 231                         // FIXME: support IPv6
 232                         using (Socket s = new Socket (AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp)) {
 233                                 if (options != null) {
 234                                         s.DontFragment = options.DontFragment;
 235                                         s.Ttl = (short) options.Ttl;
 236                                 }
 237                                 s.SendTimeout = timeout;
 238                                 s.ReceiveTimeout = timeout;
 239                                 // not sure why Identifier = 0 is unacceptable ...
 240                                 IcmpMessage send = new IcmpMessage (8, 0, identifier, 0, buffer);
 241                                 byte [] bytes = send.GetBytes ();
 242                                 s.SendBufferSize = bytes.Length;
 243                                 s.SendTo (bytes, bytes.Length, SocketFlags.None, target);
 244
 245                                 DateTime sentTime = DateTime.Now;
 246
 247                                 // receive
 248                                 bytes = new byte [100];
 249                                 do {
 250                                         EndPoint endpoint = client;
 251                                         int error = 0;
 252                                         int rc = s.ReceiveFrom_nochecks_exc (bytes, 0, 100, SocketFlags.None,
 253                                                         ref endpoint, false, out error);
 254
 255                                         if (error != 0) {
 256                                                 if (error == (int) SocketError.TimedOut) {
 257                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 258                                                 }
 259                                                 throw new NotSupportedException (String.Format ("Unexpected socket error during ping request: {0}", error));
 260                                         }
 261                                         long rtt = (long) (DateTime.Now - sentTime).TotalMilliseconds;
 262                                         int headerLength = (bytes [0] & 0xF) << 2;
 263                                         int bodyLength = rc - headerLength;
 264
 265                                         // Ping reply to different request. discard it.
 266                                         if (!((IPEndPoint) endpoint).Address.Equals (target.Address)) {
 267                                                 long t = timeout - rtt;
 268                                                 if (t <= 0)
 269                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 270                                                 s.ReceiveTimeout = (int) t;
 271                                                 continue;
 272                                         }
 273
 274                                         IcmpMessage recv = new IcmpMessage (bytes, headerLength, bodyLength);
 275
 276                                         /* discard ping reply to different request or echo requests if running on same host. */
 277                                         if (recv.Identifier != identifier || recv.Type == 8) {
 278                                                 long t = timeout - rtt;
 279                                                 if (t <= 0)
 280                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 281                                                 s.ReceiveTimeout = (int) t;
 282                                                 continue;
 283                                         }
 284
 285                                         return new PingReply (address, recv.Data, options, rtt, recv.IPStatus);
 286                                 } while (true);
 287                         }
 288                 }
 289
 290                 private PingReply SendUnprivileged (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 291                 {
 292                         DateTime sentTime = DateTime.Now;
 293
 294                         Process ping = new Process ();
 295                         string args = BuildPingArgs (address, timeout, options);
 296                         long trip_time = 0;
 297
 298                         ping.StartInfo.FileName = PingBinPath;
 299                         ping.StartInfo.Arguments = args;
 300
 301                         ping.StartInfo.CreateNoWindow = true;
 302                         ping.StartInfo.UseShellExecute = false;
 303
 304                         ping.StartInfo.RedirectStandardOutput = true;
 305                         ping.StartInfo.RedirectStandardError = true;
 306
 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.Now - sentTime).TotalMilliseconds;
 316                                 if (!ping.WaitForExit (timeout) || (ping.HasExited && ping.ExitCode == 2))
 317                                         return new PingReply (address, buffer, options, trip_time, IPStatus.TimedOut);
 318
 319                                 if (ping.ExitCode == 1)
 320                                         return new PingReply (address, buffer, options, trip_time, IPStatus.TtlExpired);
 321                         } catch (Exception) {
 322                                 return new PingReply (address, buffer, options, trip_time, IPStatus.Unknown);
 323                         } finally {
 324                                 if (ping != null) {
 325                                         if (!ping.HasExited)
 326                                                 ping.Kill ();
 327                                         ping.Dispose ();
 328                                 }
 329                         }
 330
 331                         return new PingReply (address, buffer, options, trip_time, IPStatus.Success);
 332                 }
 333
 334                 // Async
 335
 336                 public void SendAsync (IPAddress address, int timeout, byte [] buffer, object userToken)
 337                 {
 338                         SendAsync (address, default_timeout, default_buffer, new PingOptions (), userToken);
 339                 }
 340
 341                 public void SendAsync (IPAddress address, int timeout, object userToken)
 342                 {
 343                         SendAsync (address, default_timeout, default_buffer, userToken);
 344                 }
 345
 346                 public void SendAsync (IPAddress address, object userToken)
 347                 {
 348                         SendAsync (address, default_timeout, userToken);
 349                 }
 350
 351                 public void SendAsync (string hostNameOrAddress, int timeout, byte [] buffer, object userToken)
 352                 {
 353                         SendAsync (hostNameOrAddress, timeout, buffer, new PingOptions (), userToken);
 354                 }
 355
 356                 public void SendAsync (string hostNameOrAddress, int timeout, byte [] buffer, PingOptions options, object userToken)
 357                 {
 358                         IPAddress address = Dns.GetHostEntry (hostNameOrAddress).AddressList [0];
 359                         SendAsync (address, timeout, buffer, options, userToken);
 360                 }
 361
 362                 public void SendAsync (string hostNameOrAddress, int timeout, object userToken)
 363                 {
 364                         SendAsync (hostNameOrAddress, timeout, default_buffer, userToken);
 365                 }
 366
 367                 public void SendAsync (string hostNameOrAddress, object userToken)
 368                 {
 369                         SendAsync (hostNameOrAddress, default_timeout, userToken);
 370                 }
 371
 372                 public void SendAsync (IPAddress address, int timeout, byte [] buffer, PingOptions options, object userToken)
 373                 {
 374 #if NET_4_5
 375                         if ((worker != null) || (cts != null))
 376                                 throw new InvalidOperationException ("Another SendAsync operation is in progress");
 377 #else
 378                         if (worker != null)
 379                                 throw new InvalidOperationException ("Another SendAsync operation is in progress");
 380 #endif
 381
 382                         worker = new BackgroundWorker ();
 383                         worker.DoWork += delegate (object o, DoWorkEventArgs ea) {
 384                                 try {
 385                                         user_async_state = ea.Argument;
 386                                         ea.Result = Send (address, timeout, buffer, options);
 387                                 } catch (Exception ex) {
 388                                         ea.Result = ex;
 389                                 }
 390                         };
 391                         worker.WorkerSupportsCancellation = true;
 392                         worker.RunWorkerCompleted += delegate (object o, RunWorkerCompletedEventArgs ea) {
 393                                 // Note that RunWorkerCompletedEventArgs.UserState cannot be used (LAMESPEC)
 394                                 OnPingCompleted (new PingCompletedEventArgs (ea.Error, ea.Cancelled, user_async_state, ea.Result as PingReply));
 395                         };
 396                         worker.RunWorkerAsync (userToken);
 397                 }
 398
 399                 // SendAsyncCancel
 400
 401                 public void SendAsyncCancel ()
 402                 {
 403 #if NET_4_5
 404                         if (cts != null) {
 405                                 cts.Cancel ();
 406                                 return;
 407                         }
 408 #endif
 409
 410                         if (worker == null)
 411                                 throw new InvalidOperationException ("SendAsync operation is not in progress");
 412                         worker.CancelAsync ();
 413                 }
 414
 415                 // ICMP message
 416
 417                 class IcmpMessage
 418                 {
 419                         byte [] bytes;
 420
 421                         // received
 422                         public IcmpMessage (byte [] bytes, int offset, int size)
 423                         {
 424                                 this.bytes = new byte [size];
 425                                 Buffer.BlockCopy (bytes, offset, this.bytes, 0, size);
 426                         }
 427
 428                         // to be sent
 429                         public IcmpMessage (byte type, byte code, ushort identifier, ushort sequence, byte [] data)
 430                         {
 431                                 bytes = new byte [data.Length + 8];
 432                                 bytes [0] = type;
 433                                 bytes [1] = code;
 434                                 bytes [4] = (byte) (identifier & 0xFF);
 435                                 bytes [5] = (byte) ((int) identifier >> 8);
 436                                 bytes [6] = (byte) (sequence & 0xFF);
 437                                 bytes [7] = (byte) ((int) sequence >> 8);
 438                                 Buffer.BlockCopy (data, 0, bytes, 8, data.Length);
 439
 440                                 ushort checksum = ComputeChecksum (bytes);
 441                                 bytes [2] = (byte) (checksum & 0xFF);
 442                                 bytes [3] = (byte) ((int) checksum >> 8);
 443                         }
 444
 445                         public byte Type {
 446                                 get { return bytes [0]; }
 447                         }
 448
 449                         public byte Code {
 450                                 get { return bytes [1]; }
 451                         }
 452
 453                         public ushort Identifier {
 454                                 get { return (ushort) (bytes [4] + (bytes [5] << 8)); }
 455                         }
 456
 457                         public ushort Sequence {
 458                                 get { return (ushort) (bytes [6] + (bytes [7] << 8)); }
 459                         }
 460
 461                         public byte [] Data {
 462                                 get {
 463                                         byte [] data = new byte [bytes.Length - 8];
 464                                         Buffer.BlockCopy (bytes, 8, data, 0, data.Length);
 465                                         return data;
 466                                 }
 467                         }
 468
 469                         public byte [] GetBytes ()
 470                         {
 471                                 return bytes;
 472                         }
 473
 474                         static ushort ComputeChecksum (byte [] data)
 475                         {
 476                                 uint ret = 0;
 477                                 for (int i = 0; i < data.Length; i += 2) {
 478                                         ushort us = i + 1 < data.Length ? data [i + 1] : (byte) 0;
 479                                         us <<= 8;
 480                                         us += data [i];
 481                                         ret += us;
 482                                 }
 483                                 ret = (ret >> 16) + (ret & 0xFFFF);
 484                                 return (ushort) ~ ret;
 485                         }
 486
 487                         public IPStatus IPStatus {
 488                                 get {
 489                                         switch (Type) {
 490                                         case 0:
 491                                                 return IPStatus.Success;
 492                                         case 3: // destination unreacheable
 493                                                 switch (Code) {
 494                                                 case 0:
 495                                                         return IPStatus.DestinationNetworkUnreachable;
 496                                                 case 1:
 497                                                         return IPStatus.DestinationHostUnreachable;
 498                                                 case 2:
 499                                                         return IPStatus.DestinationProtocolUnreachable;
 500                                                 case 3:
 501                                                         return IPStatus.DestinationPortUnreachable;
 502                                                 case 4:
 503                                                         return IPStatus.BadOption; // FIXME: likely wrong
 504                                                 case 5:
 505                                                         return IPStatus.BadRoute; // not sure if it is correct
 506                                                 }
 507                                                 break;
 508                                         case 11:
 509                                                 switch (Code) {
 510                                                 case 0:
 511                                                         return IPStatus.TimeExceeded;
 512                                                 case 1:
 513                                                         return IPStatus.TtlReassemblyTimeExceeded;
 514                                                 }
 515                                                 break;
 516                                         case 12:
 517                                                 return IPStatus.ParameterProblem;
 518                                         case 4:
 519                                                 return IPStatus.SourceQuench;
 520                                         case 8:
 521                                                 return IPStatus.Success;
 522                                         }
 523                                         return IPStatus.Unknown;
 524                                         //throw new NotSupportedException (String.Format ("Unexpected pair of ICMP message type and code: type is {0} and code is {1}", Type, Code));
 525                                 }
 526                         }
 527                 }
 528
 529                 private string BuildPingArgs (IPAddress address, int timeout, PingOptions options)
 530                 {
 531                         CultureInfo culture = CultureInfo.InvariantCulture;
 532                         StringBuilder args = new StringBuilder ();
 533                         uint t = Convert.ToUInt32 (Math.Floor ((timeout + 1000) / 1000.0));
 534                         bool is_mac = ((int) Environment.OSVersion.Platform == 6);
 535                         if (!is_mac)
 536                                 args.AppendFormat (culture, "-q -n -c {0} -w {1} -t {2} -M ", DefaultCount, t, options.Ttl);
 537                         else
 538                                 args.AppendFormat (culture, "-q -n -c {0} -t {1} -o -m {2} ", DefaultCount, t, options.Ttl);
 539                         if (!is_mac)
 540                                 args.Append (options.DontFragment ? "do " : "dont ");
 541                         else if (options.DontFragment)
 542                                 args.Append ("-D ");
 543
 544                         args.Append (address.ToString ());
 545
 546                         return args.ToString ();
 547                 }
 548
 549 #if NET_4_5
 550                 public Task<PingReply> SendPingAsync (IPAddress address, int timeout, byte [] buffer)
 551                 {
 552                         return SendPingAsync (address, default_timeout, default_buffer, new PingOptions ());
 553                 }
 554
 555                 public Task<PingReply> SendPingAsync (IPAddress address, int timeout)
 556                 {
 557                         return SendPingAsync (address, default_timeout, default_buffer);
 558                 }
 559
 560                 public Task<PingReply> SendPingAsync (IPAddress address)
 561                 {
 562                         return SendPingAsync (address, default_timeout);
 563                 }
 564
 565                 public Task<PingReply> SendPingAsync (string hostNameOrAddress, int timeout, byte [] buffer)
 566                 {
 567                         return SendPingAsync (hostNameOrAddress, timeout, buffer, new PingOptions ());
 568                 }
 569
 570                 public Task<PingReply> SendPingAsync (string hostNameOrAddress, int timeout, byte [] buffer, PingOptions options)
 571                 {
 572                         IPAddress address = Dns.GetHostEntry (hostNameOrAddress).AddressList [0];
 573                         return SendPingAsync (address, timeout, buffer, options);
 574                 }
 575
 576                 public Task<PingReply> SendPingAsync (string hostNameOrAddress, int timeout)
 577                 {
 578                         return SendPingAsync (hostNameOrAddress, timeout, default_buffer);
 579                 }
 580
 581                 public Task<PingReply> SendPingAsync (string hostNameOrAddress)
 582                 {
 583                         return SendPingAsync (hostNameOrAddress, default_timeout);
 584                 }
 585
 586                 public Task<PingReply> SendPingAsync (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 587                 {
 588                         if ((worker != null) || (cts != null))
 589                                 throw new InvalidOperationException ("Another SendAsync operation is in progress");
 590
 591                         var task = Task<PingReply>.Factory.StartNew (
 592                                 () => Send (address, timeout, buffer, options), cts.Token);
 593
 594                         task.ContinueWith ((t) => {
 595                                 if (t.IsCanceled)
 596                                         OnPingCompleted (new PingCompletedEventArgs (null, true, null, null));
 597                                 else if (t.IsFaulted)
 598                                         OnPingCompleted (new PingCompletedEventArgs (t.Exception, false, null, null));
 599                                 else
 600                                         OnPingCompleted (new PingCompletedEventArgs (null, false, null, t.Result));
 601                         });
 602
 603                         return task;
 604                 }
 605 #endif
 606         }
 607 }
 608