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 #if NET_2_0
  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
  41 namespace System.Net.NetworkInformation {
  42         [MonoTODO ("IPv6 support is missing")]
  43         public class Ping : Component, IDisposable
  44         {
  45                 [StructLayout(LayoutKind.Sequential)]
  46                 struct cap_user_header_t
  47                 {
  48                         public UInt32 version;
  49                         public Int32 pid;
  50                 };
  51
  52                 [StructLayout(LayoutKind.Sequential)]
  53                 struct cap_user_data_t
  54                 {
  55                         public UInt32 effective;
  56                         public UInt32 permitted;
  57                         public UInt32 inheritable;
  58                 }
  59
  60                 const int DefaultCount = 1;
  61                 static readonly string [] PingBinPaths = new string [] {
  62                         "/bin/ping",
  63                         "/sbin/ping",
  64                         "/usr/sbin/ping"
  65                 };
  66                 static readonly string PingBinPath;
  67                 const int default_timeout = 4000; // 4 sec.
  68                 ushort identifier;
  69
  70                 // This value is correct as of Linux kernel version 2.6.25.9
  71                 // See /usr/include/linux/capability.h
  72                 const UInt32 linux_cap_version = 0x20071026;
  73
  74                 static readonly byte [] default_buffer = new byte [0];
  75                 static bool canSendPrivileged;
  76
  77
  78                 BackgroundWorker worker;
  79                 object user_async_state;
  80
  81                 public event PingCompletedEventHandler PingCompleted;
  82
  83                 static Ping ()
  84                 {
  85                         if (Environment.OSVersion.Platform == PlatformID.Unix) {
  86                                 CheckLinuxCapabilities ();
  87                                 if (!canSendPrivileged && WindowsIdentity.GetCurrent ().Name == "root")
  88                                         canSendPrivileged = true;
  89
  90                                 // Since different Unix systems can have different path to bin, we try some
  91                                 // of the known ones.
  92                                 foreach (string ping_path in PingBinPaths)
  93                                         if (File.Exists (ping_path)) {
  94                                                 PingBinPath = ping_path;
  95                                                 break;
  96                                         }
  97                         }
  98                         else
  99                                 canSendPrivileged = true;
 100
 101                         if (PingBinPath == null)
 102                                 PingBinPath = "/bin/ping"; // default, fallback value
 103                 }
 104
 105                 public Ping ()
 106                 {
 107                         // Generate a new random 16 bit identifier for every ping
 108                         RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider ();
 109                         byte [] randomIdentifier = new byte [2];
 110                         rng.GetBytes (randomIdentifier);
 111                         identifier = (ushort)(randomIdentifier [0] + (randomIdentifier [1] << 8));
 112                 }
 113
 114                 [DllImport ("libc", EntryPoint="capget")]
 115                 static extern int capget (ref cap_user_header_t header, ref cap_user_data_t data);
 116
 117                 static void CheckLinuxCapabilities ()
 118                 {
 119                         try {
 120                                 cap_user_header_t header = new cap_user_header_t ();
 121                                 cap_user_data_t data = new cap_user_data_t ();
 122
 123                                 header.version = linux_cap_version;
 124
 125                                 int ret = -1;
 126
 127                                 try {
 128                                         ret = capget (ref header, ref data);
 129                                 } catch (Exception) {
 130                                 }
 131
 132                                 if (ret == -1)
 133                                         return;
 134
 135                                 canSendPrivileged = (data.effective & (1 << 13)) != 0;
 136                         } catch {
 137                                 canSendPrivileged = false;
 138                         }
 139                 }
 140
 141                 void IDisposable.Dispose ()
 142                 {
 143                 }
 144
 145                 protected void OnPingCompleted (PingCompletedEventArgs e)
 146                 {
 147                         if (PingCompleted != null)
 148                                 PingCompleted (this, e);
 149                         user_async_state = null;
 150                         worker = null;
 151                 }
 152
 153                 // Sync
 154
 155                 public PingReply Send (IPAddress address)
 156                 {
 157                         return Send (address, default_timeout);
 158                 }
 159
 160                 public PingReply Send (IPAddress address, int timeout)
 161                 {
 162                         return Send (address, timeout, default_buffer);
 163                 }
 164
 165                 public PingReply Send (IPAddress address, int timeout, byte [] buffer)
 166                 {
 167                         return Send (address, timeout, buffer, new PingOptions ());
 168                 }
 169
 170                 public PingReply Send (string hostNameOrAddress)
 171                 {
 172                         return Send (hostNameOrAddress, default_timeout);
 173                 }
 174
 175                 public PingReply Send (string hostNameOrAddress, int timeout)
 176                 {
 177                         return Send (hostNameOrAddress, timeout, default_buffer);
 178                 }
 179
 180                 public PingReply Send (string hostNameOrAddress, int timeout, byte [] buffer)
 181                 {
 182                         return Send (hostNameOrAddress, timeout, buffer, new PingOptions ());
 183                 }
 184
 185                 public PingReply Send (string hostNameOrAddress, int timeout, byte [] buffer, PingOptions options)
 186                 {
 187                         IPAddress [] addresses = Dns.GetHostAddresses (hostNameOrAddress);
 188                         return Send (addresses [0], timeout, buffer, options);
 189                 }
 190
 191                 static IPAddress GetNonLoopbackIP ()
 192                 {
 193                         foreach (IPAddress addr in Dns.GetHostByName (Dns.GetHostName ()).AddressList)
 194                                 if (!IPAddress.IsLoopback (addr))
 195                                         return addr;
 196                         throw new InvalidOperationException ("Could not resolve non-loopback IP address for localhost");
 197                 }
 198
 199                 public PingReply Send (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 200                 {
 201                         if (address == null)
 202                                 throw new ArgumentNullException ("address");
 203                         if (timeout < 0)
 204                                 throw new ArgumentOutOfRangeException ("timeout", "timeout must be non-negative integer");
 205                         if (buffer == null)
 206                                 throw new ArgumentNullException ("buffer");
 207                         if (buffer.Length > 65500)
 208                                 throw new ArgumentException ("buffer");
 209                         // options can be null.
 210
 211                         if (canSendPrivileged)
 212                                 return SendPrivileged (address, timeout, buffer, options);
 213                         return SendUnprivileged (address, timeout, buffer, options);
 214                 }
 215
 216                 private PingReply SendPrivileged (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 217                 {
 218                         IPEndPoint target = new IPEndPoint (address, 0);
 219                         IPEndPoint client = new IPEndPoint (GetNonLoopbackIP (), 0);
 220
 221                         // FIXME: support IPv6
 222                         using (Socket s = new Socket (AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp)) {
 223                                 if (options != null) {
 224                                         s.DontFragment = options.DontFragment;
 225                                         s.Ttl = (short) options.Ttl;
 226                                 }
 227                                 s.SendTimeout = timeout;
 228                                 s.ReceiveTimeout = timeout;
 229                                 // not sure why Identifier = 0 is unacceptable ...
 230                                 IcmpMessage send = new IcmpMessage (8, 0, identifier, 0, buffer);
 231                                 byte [] bytes = send.GetBytes ();
 232                                 s.SendBufferSize = bytes.Length;
 233                                 s.SendTo (bytes, bytes.Length, SocketFlags.None, target);
 234
 235                                 DateTime sentTime = DateTime.Now;
 236
 237                                 // receive
 238                                 bytes = new byte [100];
 239                                 do {
 240                                         EndPoint endpoint = client;
 241                                         int error = 0;
 242                                         int rc = s.ReceiveFrom_nochecks_exc (bytes, 0, 100, SocketFlags.None,
 243                                                         ref endpoint, false, out error);
 244
 245                                         if (error != 0) {
 246                                                 if (error == (int) SocketError.TimedOut) {
 247                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 248                                                 }
 249                                                 throw new NotSupportedException (String.Format ("Unexpected socket error during ping request: {0}", error));
 250                                         }
 251                                         long rtt = (long) (DateTime.Now - sentTime).TotalMilliseconds;
 252                                         int headerLength = (bytes [0] & 0xF) << 2;
 253                                         int bodyLength = rc - headerLength;
 254
 255                                         // Ping reply to different request. discard it.
 256                                         if (!((IPEndPoint) endpoint).Address.Equals (target.Address)) {
 257                                                 long t = timeout - rtt;
 258                                                 if (t <= 0)
 259                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 260                                                 s.ReceiveTimeout = (int) t;
 261                                                 continue;
 262                                         }
 263
 264                                         IcmpMessage recv = new IcmpMessage (bytes, headerLength, bodyLength);
 265
 266                                         /* discard ping reply to different request or echo requests if running on same host. */
 267                                         if (recv.Identifier != identifier || recv.Type == 8) {
 268                                                 long t = timeout - rtt;
 269                                                 if (t <= 0)
 270                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 271                                                 s.ReceiveTimeout = (int) t;
 272                                                 continue;
 273                                         }
 274
 275                                         return new PingReply (address, recv.Data, options, rtt, recv.IPStatus);
 276                                 } while (true);
 277                         }
 278                 }
 279
 280                 private PingReply SendUnprivileged (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 281                 {
 282                         DateTime sentTime = DateTime.Now;
 283
 284                         Process ping = new Process ();
 285                         string args = BuildPingArgs (address, timeout, options);
 286                         long trip_time = 0;
 287
 288                         ping.StartInfo.FileName = PingBinPath;
 289                         ping.StartInfo.Arguments = args;
 290
 291                         ping.StartInfo.CreateNoWindow = true;
 292                         ping.StartInfo.UseShellExecute = false;
 293
 294                         ping.StartInfo.RedirectStandardOutput = true;
 295                         ping.StartInfo.RedirectStandardError = true;
 296
 297                         try {
 298                                 ping.Start ();
 299
 300 #pragma warning disable 219
 301                                 string stdout = ping.StandardOutput.ReadToEnd ();
 302                                 string stderr = ping.StandardError.ReadToEnd ();
 303 #pragma warning restore 219
 304
 305                                 trip_time = (long) (DateTime.Now - sentTime).TotalMilliseconds;
 306                                 if (!ping.WaitForExit (timeout) || (ping.HasExited && ping.ExitCode == 2))
 307                                         return new PingReply (address, buffer, options, trip_time, IPStatus.TimedOut);
 308
 309                                 if (ping.ExitCode == 1)
 310                                         return new PingReply (address, buffer, options, trip_time, IPStatus.TtlExpired);
 311                         } catch (Exception) {
 312                                 return new PingReply (address, buffer, options, trip_time, IPStatus.Unknown);
 313                         } finally {
 314                                 if (ping != null) {
 315                                         if (!ping.HasExited)
 316                                                 ping.Kill ();
 317                                         ping.Dispose ();
 318                                 }
 319                         }
 320
 321                         return new PingReply (address, buffer, options, trip_time, IPStatus.Success);
 322                 }
 323
 324                 // Async
 325
 326                 public void SendAsync (IPAddress address, int timeout, byte [] buffer, object userToken)
 327                 {
 328                         SendAsync (address, default_timeout, default_buffer, new PingOptions (), userToken);
 329                 }
 330
 331                 public void SendAsync (IPAddress address, int timeout, object userToken)
 332                 {
 333                         SendAsync (address, default_timeout, default_buffer, userToken);
 334                 }
 335
 336                 public void SendAsync (IPAddress address, object userToken)
 337                 {
 338                         SendAsync (address, default_timeout, userToken);
 339                 }
 340
 341                 public void SendAsync (string hostNameOrAddress, int timeout, byte [] buffer, object userToken)
 342                 {
 343                         SendAsync (hostNameOrAddress, timeout, buffer, new PingOptions (), userToken);
 344                 }
 345
 346                 public void SendAsync (string hostNameOrAddress, int timeout, byte [] buffer, PingOptions options, object userToken)
 347                 {
 348                         IPAddress address = Dns.GetHostEntry (hostNameOrAddress).AddressList [0];
 349                         SendAsync (address, timeout, buffer, options, userToken);
 350                 }
 351
 352                 public void SendAsync (string hostNameOrAddress, int timeout, object userToken)
 353                 {
 354                         SendAsync (hostNameOrAddress, timeout, default_buffer, userToken);
 355                 }
 356
 357                 public void SendAsync (string hostNameOrAddress, object userToken)
 358                 {
 359                         SendAsync (hostNameOrAddress, default_timeout, userToken);
 360                 }
 361
 362                 public void SendAsync (IPAddress address, int timeout, byte [] buffer, PingOptions options, object userToken)
 363                 {
 364                         if (worker != null)
 365                                 throw new InvalidOperationException ("Another SendAsync operation is in progress");
 366
 367                         worker = new BackgroundWorker ();
 368                         worker.DoWork += delegate (object o, DoWorkEventArgs ea) {
 369                                 try {
 370                                         user_async_state = ea.Argument;
 371                                         ea.Result = Send (address, timeout, buffer, options);
 372                                 } catch (Exception ex) {
 373                                         ea.Result = ex;
 374                                 }
 375                         };
 376                         worker.WorkerSupportsCancellation = true;
 377                         worker.RunWorkerCompleted += delegate (object o, RunWorkerCompletedEventArgs ea) {
 378                                 // Note that RunWorkerCompletedEventArgs.UserState cannot be used (LAMESPEC)
 379                                 OnPingCompleted (new PingCompletedEventArgs (ea.Error, ea.Cancelled, user_async_state, ea.Result as PingReply));
 380                         };
 381                         worker.RunWorkerAsync (userToken);
 382                 }
 383
 384                 // SendAsyncCancel
 385
 386                 public void SendAsyncCancel ()
 387                 {
 388                         if (worker == null)
 389                                 throw new InvalidOperationException ("SendAsync operation is not in progress");
 390                         worker.CancelAsync ();
 391                 }
 392
 393                 // ICMP message
 394
 395                 class IcmpMessage
 396                 {
 397                         byte [] bytes;
 398
 399                         // received
 400                         public IcmpMessage (byte [] bytes, int offset, int size)
 401                         {
 402                                 this.bytes = new byte [size];
 403                                 Buffer.BlockCopy (bytes, offset, this.bytes, 0, size);
 404                         }
 405
 406                         // to be sent
 407                         public IcmpMessage (byte type, byte code, ushort identifier, ushort sequence, byte [] data)
 408                         {
 409                                 bytes = new byte [data.Length + 8];
 410                                 bytes [0] = type;
 411                                 bytes [1] = code;
 412                                 bytes [4] = (byte) (identifier & 0xFF);
 413                                 bytes [5] = (byte) ((int) identifier >> 8);
 414                                 bytes [6] = (byte) (sequence & 0xFF);
 415                                 bytes [7] = (byte) ((int) sequence >> 8);
 416                                 Buffer.BlockCopy (data, 0, bytes, 8, data.Length);
 417
 418                                 ushort checksum = ComputeChecksum (bytes);
 419                                 bytes [2] = (byte) (checksum & 0xFF);
 420                                 bytes [3] = (byte) ((int) checksum >> 8);
 421                         }
 422
 423                         public byte Type {
 424                                 get { return bytes [0]; }
 425                         }
 426
 427                         public byte Code {
 428                                 get { return bytes [1]; }
 429                         }
 430
 431                         public ushort Identifier {
 432                                 get { return (ushort) (bytes [4] + (bytes [5] << 8)); }
 433                         }
 434
 435                         public ushort Sequence {
 436                                 get { return (ushort) (bytes [6] + (bytes [7] << 8)); }
 437                         }
 438
 439                         public byte [] Data {
 440                                 get {
 441                                         byte [] data = new byte [bytes.Length - 8];
 442                                         Buffer.BlockCopy (bytes, 8, data, 0, data.Length);
 443                                         return data;
 444                                 }
 445                         }
 446
 447                         public byte [] GetBytes ()
 448                         {
 449                                 return bytes;
 450                         }
 451
 452                         static ushort ComputeChecksum (byte [] data)
 453                         {
 454                                 uint ret = 0;
 455                                 for (int i = 0; i < data.Length; i += 2) {
 456                                         ushort us = i + 1 < data.Length ? data [i + 1] : (byte) 0;
 457                                         us <<= 8;
 458                                         us += data [i];
 459                                         ret += us;
 460                                 }
 461                                 ret = (ret >> 16) + (ret & 0xFFFF);
 462                                 return (ushort) ~ ret;
 463                         }
 464
 465                         public IPStatus IPStatus {
 466                                 get {
 467                                         switch (Type) {
 468                                         case 0:
 469                                                 return IPStatus.Success;
 470                                         case 3: // destination unreacheable
 471                                                 switch (Code) {
 472                                                 case 0:
 473                                                         return IPStatus.DestinationNetworkUnreachable;
 474                                                 case 1:
 475                                                         return IPStatus.DestinationHostUnreachable;
 476                                                 case 2:
 477                                                         return IPStatus.DestinationProtocolUnreachable;
 478                                                 case 3:
 479                                                         return IPStatus.DestinationPortUnreachable;
 480                                                 case 4:
 481                                                         return IPStatus.BadOption; // FIXME: likely wrong
 482                                                 case 5:
 483                                                         return IPStatus.BadRoute; // not sure if it is correct
 484                                                 }
 485                                                 break;
 486                                         case 11:
 487                                                 switch (Code) {
 488                                                 case 0:
 489                                                         return IPStatus.TimeExceeded;
 490                                                 case 1:
 491                                                         return IPStatus.TtlReassemblyTimeExceeded;
 492                                                 }
 493                                                 break;
 494                                         case 12:
 495                                                 return IPStatus.ParameterProblem;
 496                                         case 4:
 497                                                 return IPStatus.SourceQuench;
 498                                         case 8:
 499                                                 return IPStatus.Success;
 500                                         }
 501                                         return IPStatus.Unknown;
 502                                         //throw new NotSupportedException (String.Format ("Unexpected pair of ICMP message type and code: type is {0} and code is {1}", Type, Code));
 503                                 }
 504                         }
 505                 }
 506
 507                 private string BuildPingArgs (IPAddress address, int timeout, PingOptions options)
 508                 {
 509                         CultureInfo culture = CultureInfo.InvariantCulture;
 510                         StringBuilder args = new StringBuilder ();
 511                         uint t = Convert.ToUInt32 (Math.Floor ((timeout + 1000) / 1000.0));
 512 #if NET_2_0
 513                         bool is_mac = ((int) Environment.OSVersion.Platform == 6);
 514                         if (!is_mac)
 515 #endif
 516                                 args.AppendFormat (culture, "-q -n -c {0} -w {1} -t {2} -M ", DefaultCount, t, options.Ttl);
 517 #if NET_2_0
 518                         else
 519                                 args.AppendFormat (culture, "-q -n -c {0} -t {1} -o -m {2} ", DefaultCount, t, options.Ttl);
 520                         if (!is_mac)
 521 #endif
 522                                 args.Append (options.DontFragment ? "do " : "dont ");
 523 #if NET_2_0
 524                         else if (options.DontFragment)
 525                                 args.Append ("-D ");
 526 #endif
 527
 528                         args.Append (address.ToString ());
 529
 530                         return args.ToString ();
 531                 }
 532
 533         }
 534 }
 535 #endif
 536