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.Runtime.InteropServices;
  39
  40 namespace System.Net.NetworkInformation {
  41         [MonoTODO ("IPv6 support is missing")]
  42         public class Ping : Component, IDisposable
  43         {
  44                 [StructLayout(LayoutKind.Sequential)]
  45                 struct cap_user_header_t
  46                 {
  47                         public UInt32 version;
  48                         public Int32 pid;
  49                 };
  50
  51                 [StructLayout(LayoutKind.Sequential)]
  52                 struct cap_user_data_t
  53                 {
  54                         public UInt32 effective;
  55                         public UInt32 permitted;
  56                         public UInt32 inheritable;
  57                 }
  58
  59                 const int DefaultCount = 1;
  60                 static readonly string [] PingBinPaths = new string [] {
  61                         "/bin/ping",
  62                         "/sbin/ping",
  63                         "/usr/sbin/ping"
  64                 };
  65                 static readonly string PingBinPath;
  66                 const int default_timeout = 4000; // 4 sec.
  67                 const int identifier = 1; // no need to be const, but there's no place to change it.
  68
  69                 // This value is correct as of Linux kernel version 2.6.25.9
  70                 // See /usr/include/linux/capability.h
  71                 const UInt32 linux_cap_version = 0x20071026;
  72
  73                 static readonly byte [] default_buffer = new byte [0];
  74                 static bool canSendPrivileged;
  75
  76
  77                 BackgroundWorker worker;
  78                 object user_async_state;
  79
  80                 public event PingCompletedEventHandler PingCompleted;
  81
  82                 static Ping ()
  83                 {
  84                         if (Environment.OSVersion.Platform == PlatformID.Unix) {
  85                                 CheckLinuxCapabilities ();
  86                                 if (!canSendPrivileged && WindowsIdentity.GetCurrent ().Name == "root")
  87                                         canSendPrivileged = true;
  88
  89                                 // Since different Unix systems can have different path to bin, we try some
  90                                 // of the known ones.
  91                                 foreach (string ping_path in PingBinPaths)
  92                                         if (File.Exists (ping_path)) {
  93                                                 PingBinPath = ping_path;
  94                                                 break;
  95                                         }
  96                         }
  97                         else
  98                                 canSendPrivileged = true;
  99
 100                         if (PingBinPath == null)
 101                                 PingBinPath = "/bin/ping"; // default, fallback value
 102                 }
 103
 104                 public Ping ()
 105                 {
 106                 }
 107
 108                 [DllImport ("libc", EntryPoint="capget")]
 109                 static extern int capget (ref cap_user_header_t header, ref cap_user_data_t data);
 110
 111                 static void CheckLinuxCapabilities ()
 112                 {
 113                         try {
 114                                 cap_user_header_t header = new cap_user_header_t ();
 115                                 cap_user_data_t data = new cap_user_data_t ();
 116
 117                                 header.version = linux_cap_version;
 118
 119                                 int ret = -1;
 120
 121                                 try {
 122                                         ret = capget (ref header, ref data);
 123                                 } catch (Exception) {
 124                                 }
 125
 126                                 if (ret == -1)
 127                                         return;
 128
 129                                 canSendPrivileged = (data.effective & (1 << 13)) != 0;
 130                         } catch {
 131                                 canSendPrivileged = false;
 132                         }
 133                 }
 134
 135                 void IDisposable.Dispose ()
 136                 {
 137                 }
 138
 139                 protected void OnPingCompleted (PingCompletedEventArgs e)
 140                 {
 141                         if (PingCompleted != null)
 142                                 PingCompleted (this, e);
 143                         user_async_state = null;
 144                         worker = null;
 145                 }
 146
 147                 // Sync
 148
 149                 public PingReply Send (IPAddress address)
 150                 {
 151                         return Send (address, default_timeout);
 152                 }
 153
 154                 public PingReply Send (IPAddress address, int timeout)
 155                 {
 156                         return Send (address, timeout, default_buffer);
 157                 }
 158
 159                 public PingReply Send (IPAddress address, int timeout, byte [] buffer)
 160                 {
 161                         return Send (address, timeout, buffer, new PingOptions ());
 162                 }
 163
 164                 public PingReply Send (string hostNameOrAddress)
 165                 {
 166                         return Send (hostNameOrAddress, default_timeout);
 167                 }
 168
 169                 public PingReply Send (string hostNameOrAddress, int timeout)
 170                 {
 171                         return Send (hostNameOrAddress, timeout, default_buffer);
 172                 }
 173
 174                 public PingReply Send (string hostNameOrAddress, int timeout, byte [] buffer)
 175                 {
 176                         return Send (hostNameOrAddress, timeout, buffer, new PingOptions ());
 177                 }
 178
 179                 public PingReply Send (string hostNameOrAddress, int timeout, byte [] buffer, PingOptions options)
 180                 {
 181                         IPAddress [] addresses = Dns.GetHostAddresses (hostNameOrAddress);
 182                         return Send (addresses [0], timeout, buffer, options);
 183                 }
 184
 185                 static IPAddress GetNonLoopbackIP ()
 186                 {
 187                         foreach (IPAddress addr in Dns.GetHostByName (Dns.GetHostName ()).AddressList)
 188                                 if (!IPAddress.IsLoopback (addr))
 189                                         return addr;
 190                         throw new InvalidOperationException ("Could not resolve non-loopback IP address for localhost");
 191                 }
 192
 193                 public PingReply Send (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 194                 {
 195                         if (address == null)
 196                                 throw new ArgumentNullException ("address");
 197                         if (timeout < 0)
 198                                 throw new ArgumentOutOfRangeException ("timeout", "timeout must be non-negative integer");
 199                         if (buffer == null)
 200                                 throw new ArgumentNullException ("buffer");
 201                         if (buffer.Length > 65500)
 202                                 throw new ArgumentException ("buffer");
 203                         // options can be null.
 204
 205                         if (canSendPrivileged)
 206                                 return SendPrivileged (address, timeout, buffer, options);
 207                         return SendUnprivileged (address, timeout, buffer, options);
 208                 }
 209
 210                 private PingReply SendPrivileged (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 211                 {
 212                         IPEndPoint target = new IPEndPoint (address, 0);
 213                         IPEndPoint client = new IPEndPoint (GetNonLoopbackIP (), 0);
 214
 215                         // FIXME: support IPv6
 216                         using (Socket s = new Socket (AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp)) {
 217                                 if (options != null) {
 218                                         s.DontFragment = options.DontFragment;
 219                                         s.Ttl = (short) options.Ttl;
 220                                 }
 221                                 s.SendTimeout = timeout;
 222                                 s.ReceiveTimeout = timeout;
 223                                 // not sure why Identifier = 0 is unacceptable ...
 224                                 IcmpMessage send = new IcmpMessage (8, 0, identifier, 0, buffer);
 225                                 byte [] bytes = send.GetBytes ();
 226                                 s.SendBufferSize = bytes.Length;
 227                                 s.SendTo (bytes, bytes.Length, SocketFlags.None, target);
 228
 229                                 DateTime sentTime = DateTime.Now;
 230
 231                                 // receive
 232                                 bytes = new byte [100];
 233                                 do {
 234                                         EndPoint endpoint = client;
 235                                         int error = 0;
 236                                         int rc = s.ReceiveFrom_nochecks_exc (bytes, 0, 100, SocketFlags.None,
 237                                                         ref endpoint, false, out error);
 238
 239                                         if (error != 0) {
 240                                                 if (error == (int) SocketError.TimedOut) {
 241                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 242                                                 }
 243                                                 throw new NotSupportedException (String.Format ("Unexpected socket error during ping request: {0}", error));
 244                                         }
 245                                         long rtt = (long) (DateTime.Now - sentTime).TotalMilliseconds;
 246                                         int headerLength = (bytes [0] & 0xF) << 2;
 247                                         int bodyLength = rc - headerLength;
 248
 249                                         // Ping reply to different request. discard it.
 250                                         if (!((IPEndPoint) endpoint).Address.Equals (target.Address)) {
 251                                                 long t = timeout - rtt;
 252                                                 if (t <= 0)
 253                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 254                                                 s.ReceiveTimeout = (int) t;
 255                                                 continue;
 256                                         }
 257
 258                                         IcmpMessage recv = new IcmpMessage (bytes, headerLength, bodyLength);
 259
 260                                         /* discard ping reply to different request or echo requests if running on same host. */
 261                                         if (recv.Identifier != identifier || recv.Type == 8) {
 262                                                 long t = timeout - rtt;
 263                                                 if (t <= 0)
 264                                                         return new PingReply (null, new byte [0], options, 0, IPStatus.TimedOut);
 265                                                 s.ReceiveTimeout = (int) t;
 266                                                 continue;
 267                                         }
 268
 269                                         return new PingReply (address, recv.Data, options, rtt, recv.IPStatus);
 270                                 } while (true);
 271                         }
 272                 }
 273
 274                 private PingReply SendUnprivileged (IPAddress address, int timeout, byte [] buffer, PingOptions options)
 275                 {
 276                         DateTime sentTime = DateTime.Now;
 277
 278                         Process ping = new Process ();
 279                         string args = BuildPingArgs (address, timeout, options);
 280                         long trip_time = 0;
 281
 282                         ping.StartInfo.FileName = PingBinPath;
 283                         ping.StartInfo.Arguments = args;
 284
 285                         ping.StartInfo.CreateNoWindow = true;
 286                         ping.StartInfo.UseShellExecute = false;
 287
 288                         ping.StartInfo.RedirectStandardOutput = true;
 289                         ping.StartInfo.RedirectStandardError = true;
 290
 291                         try {
 292                                 ping.Start ();
 293
 294 #pragma warning disable 219
 295                         // No need to read stdout or stderr as long as the output is less than 4k on linux <= 2.6.11 and 65k after that
 296                         //      string stdout = ping.StandardOutput.ReadToEnd ();
 297                         //      string stderr = ping.StandardError.ReadToEnd ();
 298 #pragma warning restore 219
 299
 300                                 trip_time = (long) (DateTime.Now - sentTime).TotalMilliseconds;
 301                                 if (!ping.WaitForExit (timeout) || (ping.HasExited && ping.ExitCode == 2))
 302                                         return new PingReply (address, buffer, options, trip_time, IPStatus.TimedOut);
 303
 304                                 if (ping.ExitCode == 1)
 305                                         return new PingReply (address, buffer, options, trip_time, IPStatus.TtlExpired);
 306                         } catch (Exception) {
 307                                 return new PingReply (address, buffer, options, trip_time, IPStatus.Unknown);
 308                         } finally {
 309                                 if (ping != null) {
 310                                         if (!ping.HasExited)
 311                                                 ping.Kill ();
 312                                         ping.Dispose ();
 313                                 }
 314                         }
 315
 316                         return new PingReply (address, buffer, options, trip_time, IPStatus.Success);
 317                 }
 318
 319                 // Async
 320
 321                 public void SendAsync (IPAddress address, int timeout, byte [] buffer, object userToken)
 322                 {
 323                         SendAsync (address, default_timeout, default_buffer, new PingOptions (), userToken);
 324                 }
 325
 326                 public void SendAsync (IPAddress address, int timeout, object userToken)
 327                 {
 328                         SendAsync (address, default_timeout, default_buffer, userToken);
 329                 }
 330
 331                 public void SendAsync (IPAddress address, object userToken)
 332                 {
 333                         SendAsync (address, default_timeout, userToken);
 334                 }
 335
 336                 public void SendAsync (string hostNameOrAddress, int timeout, byte [] buffer, object userToken)
 337                 {
 338                         SendAsync (hostNameOrAddress, timeout, buffer, new PingOptions (), userToken);
 339                 }
 340
 341                 public void SendAsync (string hostNameOrAddress, int timeout, byte [] buffer, PingOptions options, object userToken)
 342                 {
 343                         IPAddress address = Dns.GetHostEntry (hostNameOrAddress).AddressList [0];
 344                         SendAsync (address, timeout, buffer, options, userToken);
 345                 }
 346
 347                 public void SendAsync (string hostNameOrAddress, int timeout, object userToken)
 348                 {
 349                         SendAsync (hostNameOrAddress, timeout, default_buffer, userToken);
 350                 }
 351
 352                 public void SendAsync (string hostNameOrAddress, object userToken)
 353                 {
 354                         SendAsync (hostNameOrAddress, default_timeout, userToken);
 355                 }
 356
 357                 public void SendAsync (IPAddress address, int timeout, byte [] buffer, PingOptions options, object userToken)
 358                 {
 359                         if (worker != null)
 360                                 throw new InvalidOperationException ("Another SendAsync operation is in progress");
 361
 362                         worker = new BackgroundWorker ();
 363                         worker.DoWork += delegate (object o, DoWorkEventArgs ea) {
 364                                 try {
 365                                         user_async_state = ea.Argument;
 366                                         ea.Result = Send (address, timeout, buffer, options);
 367                                 } catch (Exception ex) {
 368                                         ea.Result = ex;
 369                                 }
 370                         };
 371                         worker.WorkerSupportsCancellation = true;
 372                         worker.RunWorkerCompleted += delegate (object o, RunWorkerCompletedEventArgs ea) {
 373                                 // Note that RunWorkerCompletedEventArgs.UserState cannot be used (LAMESPEC)
 374                                 OnPingCompleted (new PingCompletedEventArgs (ea.Error, ea.Cancelled, user_async_state, ea.Result as PingReply));
 375                         };
 376                         worker.RunWorkerAsync (userToken);
 377                 }
 378
 379                 // SendAsyncCancel
 380
 381                 public void SendAsyncCancel ()
 382                 {
 383                         if (worker == null)
 384                                 throw new InvalidOperationException ("SendAsync operation is not in progress");
 385                         worker.CancelAsync ();
 386                 }
 387
 388                 // ICMP message
 389
 390                 class IcmpMessage
 391                 {
 392                         byte [] bytes;
 393
 394                         // received
 395                         public IcmpMessage (byte [] bytes, int offset, int size)
 396                         {
 397                                 this.bytes = new byte [size];
 398                                 Buffer.BlockCopy (bytes, offset, this.bytes, 0, size);
 399                         }
 400
 401                         // to be sent
 402                         public IcmpMessage (byte type, byte code, short identifier, short sequence, byte [] data)
 403                         {
 404                                 bytes = new byte [data.Length + 8];
 405                                 bytes [0] = type;
 406                                 bytes [1] = code;
 407                                 bytes [4] = (byte) (identifier & 0xFF);
 408                                 bytes [5] = (byte) ((int) identifier >> 8);
 409                                 bytes [6] = (byte) (sequence & 0xFF);
 410                                 bytes [7] = (byte) ((int) sequence >> 8);
 411                                 Buffer.BlockCopy (data, 0, bytes, 8, data.Length);
 412
 413                                 ushort checksum = ComputeChecksum (bytes);
 414                                 bytes [2] = (byte) (checksum & 0xFF);
 415                                 bytes [3] = (byte) ((int) checksum >> 8);
 416                         }
 417
 418                         public byte Type {
 419                                 get { return bytes [0]; }
 420                         }
 421
 422                         public byte Code {
 423                                 get { return bytes [1]; }
 424                         }
 425
 426                         public byte Identifier {
 427                                 get { return (byte) (bytes [4] + (bytes [5] << 8)); }
 428                         }
 429
 430                         public byte Sequence {
 431                                 get { return (byte) (bytes [6] + (bytes [7] << 8)); }
 432                         }
 433
 434                         public byte [] Data {
 435                                 get {
 436                                         byte [] data = new byte [bytes.Length - 8];
 437                                         Buffer.BlockCopy (bytes, 0, data, 0, data.Length);
 438                                         return data;
 439                                 }
 440                         }
 441
 442                         public byte [] GetBytes ()
 443                         {
 444                                 return bytes;
 445                         }
 446
 447                         static ushort ComputeChecksum (byte [] data)
 448                         {
 449                                 uint ret = 0;
 450                                 for (int i = 0; i < data.Length; i += 2) {
 451                                         ushort us = i + 1 < data.Length ? data [i + 1] : (byte) 0;
 452                                         us <<= 8;
 453                                         us += data [i];
 454                                         ret += us;
 455                                 }
 456                                 ret = (ret >> 16) + (ret & 0xFFFF);
 457                                 return (ushort) ~ ret;
 458                         }
 459
 460                         public IPStatus IPStatus {
 461                                 get {
 462                                         switch (Type) {
 463                                         case 0:
 464                                                 return IPStatus.Success;
 465                                         case 3: // destination unreacheable
 466                                                 switch (Code) {
 467                                                 case 0:
 468                                                         return IPStatus.DestinationNetworkUnreachable;
 469                                                 case 1:
 470                                                         return IPStatus.DestinationHostUnreachable;
 471                                                 case 2:
 472                                                         return IPStatus.DestinationProtocolUnreachable;
 473                                                 case 3:
 474                                                         return IPStatus.DestinationPortUnreachable;
 475                                                 case 4:
 476                                                         return IPStatus.BadOption; // FIXME: likely wrong
 477                                                 case 5:
 478                                                         return IPStatus.BadRoute; // not sure if it is correct
 479                                                 }
 480                                                 break;
 481                                         case 11:
 482                                                 switch (Code) {
 483                                                 case 0:
 484                                                         return IPStatus.TimeExceeded;
 485                                                 case 1:
 486                                                         return IPStatus.TtlReassemblyTimeExceeded;
 487                                                 }
 488                                                 break;
 489                                         case 12:
 490                                                 return IPStatus.ParameterProblem;
 491                                         case 4:
 492                                                 return IPStatus.SourceQuench;
 493                                         case 8:
 494                                                 return IPStatus.Success;
 495                                         }
 496                                         return IPStatus.Unknown;
 497                                         //throw new NotSupportedException (String.Format ("Unexpected pair of ICMP message type and code: type is {0} and code is {1}", Type, Code));
 498                                 }
 499                         }
 500                 }
 501
 502                 private string BuildPingArgs (IPAddress address, int timeout, PingOptions options)
 503                 {
 504                         CultureInfo culture = CultureInfo.InvariantCulture;
 505                         StringBuilder args = new StringBuilder ();
 506                         uint t = Convert.ToUInt32 (Math.Floor ((timeout + 1000) / 1000.0));
 507 #if NET_2_0
 508                         bool is_mac = ((int) Environment.OSVersion.Platform == 6);
 509                         if (!is_mac)
 510 #endif
 511                                 args.AppendFormat (culture, "-q -n -c {0} -w {1} -t {2} -M ", DefaultCount, t, options.Ttl);
 512 #if NET_2_0
 513                         else
 514                                 args.AppendFormat (culture, "-q -n -c {0} -t {1} -o -m {2} ", DefaultCount, t, options.Ttl);
 515                         if (!is_mac)
 516 #endif
 517                                 args.Append (options.DontFragment ? "do " : "dont ");
 518 #if NET_2_0
 519                         else if (options.DontFragment)
 520                                 args.Append ("-D ");
 521 #endif
 522
 523                         args.Append (address.ToString ());
 524
 525                         return args.ToString ();
 526                 }
 527
 528         }
 529 }
 530 #endif
 531