src/anytun.cpp

   1 /*
   2  *  anytun
   3  *
   4  *  The secure anycast tunneling protocol (satp) defines a protocol used
   5  *  for communication between any combination of unicast and anycast
   6  *  tunnel endpoints.  It has less protocol overhead than IPSec in Tunnel
   7  *  mode and allows tunneling of every ETHER TYPE protocol (e.g.
   8  *  ethernet, ip, arp ...). satp directly includes cryptography and
   9  *  message authentication based on the methodes used by SRTP.  It is
  10  *  intended to deliver a generic, scaleable and secure solution for
  11  *  tunneling and relaying of packets of any protocol.
  12  *
  13  *
  14  *  Copyright (C) 2007 anytun.org <satp@wirdorange.org>
  15  *
  16  *  This program is free software; you can redistribute it and/or modify
  17  *  it under the terms of the GNU General Public License version 2
  18  *  as published by the Free Software Foundation.
  19  *
  20  *  This program is distributed in the hope that it will be useful,
  21  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  *  GNU General Public License for more details.
  24  *
  25  *  You should have received a copy of the GNU General Public License
  26  *  along with this program (see the file COPYING included with this
  27  *  distribution); if not, write to the Free Software Foundation, Inc.,
  28  *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  29  */
  30
  31 #include <iostream>
  32 #include <fstream>
  33 #include <poll.h>
  34 #include <fcntl.h>
  35 #include <pwd.h>
  36 #include <grp.h>
  37 #include <sys/wait.h>
  38 #include <sys/stat.h>
  39 #include <unistd.h>
  40
  41 #include <pthread.h>
  42 #include <gcrypt.h>
  43 #include <cerrno>     // for ENOMEM
  44
  45 #include "datatypes.h"
  46
  47 #include "log.h"
  48 #include "buffer.h"
  49 #include "plainPacket.h"
  50 #include "encryptedPacket.h"
  51 #include "cipher.h"
  52 #include "keyDerivation.h"
  53 #include "authAlgo.h"
  54 #include "cipherFactory.h"
  55 #include "authAlgoFactory.h"
  56 #include "keyDerivationFactory.h"
  57 #include "signalController.h"
  58 #include "packetSource.h"
  59 #include "tunDevice.h"
  60 #include "options.h"
  61 #include "seqWindow.h"
  62 #include "connectionList.h"
  63 #include "routingTable.h"
  64 #include "networkAddress.h"
  65
  66 #include "syncQueue.h"
  67 #include "syncCommand.h"
  68
  69 #ifndef ANYTUN_NOSYNC
  70 #include "syncSocketHandler.h"
  71 #include "syncListenSocket.h"
  72
  73 #include "syncSocket.h"
  74 #include "syncClientSocket.h"
  75 #endif
  76
  77 #include "threadParam.h"
  78
  79 #define MAX_PACKET_LENGTH 1600
  80
  81 #define SESSION_KEYLEN_AUTH 20   // TODO: hardcoded size
  82 #define SESSION_KEYLEN_ENCR 16   // TODO: hardcoded size
  83 #define SESSION_KEYLEN_SALT 14   // TODO: hardcoded size
  84
  85 void createConnection(const std::string & remote_host, u_int16_t remote_port, ConnectionList & cl, u_int16_t seqSize, SyncQueue & queue, mux_t mux)
  86 {
  87         SeqWindow * seq= new SeqWindow(seqSize);
  88         seq_nr_t seq_nr_=0;
  89   KeyDerivation * kd = KeyDerivationFactory::create(gOpt.getKdPrf());
  90   kd->init(gOpt.getKey(), gOpt.getSalt());
  91   cLog.msg(Log::PRIO_NOTICE) << "added connection remote host " << remote_host << ":" << remote_port;
  92         ConnectionParam connparam ( (*kd),  (*seq), seq_nr_, remote_host,  remote_port);
  93         cl.addConnection(connparam,mux);
  94         NetworkAddress addr(ipv4,gOpt.getIfconfigParamRemoteNetmask().c_str());
  95         NetworkPrefix prefix(addr,32);
  96         gRoutingTable.addRoute(prefix,mux);
  97   SyncCommand sc (cl,mux);
  98         queue.push(sc);
  99   SyncCommand sc2 (prefix);
 100         queue.push(sc2);
 101 }
 102
 103 bool checkPacketSeqNr(EncryptedPacket& pack,ConnectionParam& conn)
 104 {
 105         // compare sender_id and seq with window
 106         if(conn.seq_window_.hasSeqNr(pack.getSenderId(), pack.getSeqNr()))
 107         {
 108                 cLog.msg(Log::PRIO_NOTICE) << "Replay attack from " << conn.remote_host_<<":"<< conn.remote_port_
 109                                << " seq:"<<pack.getSeqNr() << " sid: "<<pack.getSenderId();
 110                 return false;
 111         }
 112
 113         conn.seq_window_.addSeqNr(pack.getSenderId(), pack.getSeqNr());
 114         return true;
 115 }
 116
 117 void* sender(void* p)
 118 {
 119   try
 120   {
 121     ThreadParam* param = reinterpret_cast<ThreadParam*>(p);
 122
 123     std::auto_ptr<Cipher> c(CipherFactory::create(gOpt.getCipher()));
 124     std::auto_ptr<AuthAlgo> a(AuthAlgoFactory::create(gOpt.getAuthAlgo()) );
 125
 126     PlainPacket plain_packet(MAX_PACKET_LENGTH);
 127     EncryptedPacket encrypted_packet(MAX_PACKET_LENGTH);
 128
 129     Buffer session_key(u_int32_t(SESSION_KEYLEN_ENCR));             // TODO: hardcoded size
 130     Buffer session_salt(u_int32_t(SESSION_KEYLEN_SALT));            // TODO: hardcoded size
 131     Buffer session_auth_key(u_int32_t(SESSION_KEYLEN_AUTH));        // TODO: hardcoded size
 132
 133         //TODO replace mux
 134     u_int16_t mux = gOpt.getMux();
 135     while(1)
 136     {
 137       plain_packet.setLength(MAX_PACKET_LENGTH);
 138       encrypted_packet.withAuthTag(false);
 139       encrypted_packet.setLength(MAX_PACKET_LENGTH);
 140
 141           // read packet from device
 142       u_int32_t len = param->dev.read(plain_packet.getPayload(), plain_packet.getPayloadLength());
 143       plain_packet.setPayloadLength(len);
 144           // set payload type
 145       if(param->dev.getType() == TYPE_TUN)
 146         plain_packet.setPayloadType(PAYLOAD_TYPE_TUN);
 147       else if(param->dev.getType() == TYPE_TAP)
 148         plain_packet.setPayloadType(PAYLOAD_TYPE_TAP);
 149       else
 150         plain_packet.setPayloadType(0);
 151
 152       if(param->cl.empty())
 153         continue;
 154           //std::cout << "got Packet for plain "<<plain_packet.getDstAddr().toString();
 155       mux = gRoutingTable.getRoute(plain_packet.getDstAddr());
 156           //std::cout << " -> "<<mux << std::endl;
 157       ConnectionMap::iterator cit = param->cl.getConnection(mux);
 158       if(cit==param->cl.getEnd())
 159         continue;
 160       ConnectionParam & conn = cit->second;
 161
 162       if(conn.remote_host_==""||!conn.remote_port_)
 163         continue;
 164           // generate packet-key TODO: do this only when needed
 165       conn.kd_.generate(LABEL_SATP_ENCRYPTION, conn.seq_nr_, session_key);
 166       conn.kd_.generate(LABEL_SATP_SALT, conn.seq_nr_, session_salt);
 167
 168       c->setKey(session_key);
 169       c->setSalt(session_salt);
 170
 171           // encrypt packet
 172       c->encrypt(plain_packet, encrypted_packet, conn.seq_nr_, gOpt.getSenderId(), mux);
 173
 174       encrypted_packet.setHeader(conn.seq_nr_, gOpt.getSenderId(), mux);
 175       conn.seq_nr_++;
 176
 177           // add authentication tag
 178       if(a->getMaxLength()) {
 179         encrypted_packet.addAuthTag();
 180         conn.kd_.generate(LABEL_SATP_MSG_AUTH, encrypted_packet.getSeqNr(), session_auth_key);
 181         a->setKey(session_auth_key);
 182         a->generate(encrypted_packet);
 183       }
 184       try
 185       {
 186         param->src.send(encrypted_packet.getBuf(), encrypted_packet.getLength(), conn.remote_host_, conn.remote_port_);
 187       }
 188       catch (std::exception e)
 189       {
 190             // ignoring icmp port unreachable :) and other socket errors :(
 191       }
 192     }
 193   }
 194   catch(std::exception e)
 195   {
 196     cLog.msg(Log::PRIO_ERR) << "sender thread died due to an uncaught exception: " << e.what();
 197   }
 198   pthread_exit(NULL);
 199 }
 200
 201 #ifndef ANYTUN_NOSYNC
 202 void* syncConnector(void* p )
 203 {
 204         ThreadParam* param = reinterpret_cast<ThreadParam*>(p);
 205
 206         SocketHandler h;
 207         SyncClientSocket sock(h,param->cl);
 208         //      sock.EnableSSL();
 209         sock.Open( param->connto.host, param->connto.port);
 210         h.Add(&sock);
 211         while (h.GetCount())
 212         {
 213                 h.Select();
 214         }
 215   pthread_exit(NULL);
 216 }
 217
 218 void* syncListener(void* p )
 219 {
 220         ThreadParam* param = reinterpret_cast<ThreadParam*>(p);
 221
 222         SyncSocketHandler h(param->queue);
 223         SyncListenSocket<SyncSocket,ConnectionList> l(h,param->cl);
 224
 225         if (l.Bind(gOpt.getLocalSyncPort()))
 226                 pthread_exit(NULL);
 227
 228         Utility::ResolveLocal(); // resolve local hostname
 229         h.Add(&l);
 230         h.Select(1,0);
 231         while (1) {
 232                 h.Select(1,0);
 233         }
 234 }
 235 #endif
 236
 237 void* receiver(void* p)
 238 {
 239   try
 240   {
 241     ThreadParam* param = reinterpret_cast<ThreadParam*>(p);
 242
 243     std::auto_ptr<Cipher> c( CipherFactory::create(gOpt.getCipher()) );
 244     std::auto_ptr<AuthAlgo> a( AuthAlgoFactory::create(gOpt.getAuthAlgo()) );
 245
 246     EncryptedPacket encrypted_packet(MAX_PACKET_LENGTH);
 247     PlainPacket plain_packet(MAX_PACKET_LENGTH);
 248
 249     Buffer session_key(u_int32_t(SESSION_KEYLEN_ENCR));             // TODO: hardcoded size
 250     Buffer session_salt(u_int32_t(SESSION_KEYLEN_SALT));            // TODO: hardcoded size
 251     Buffer session_auth_key(u_int32_t(SESSION_KEYLEN_AUTH));        // TODO: hardcoded size
 252
 253     while(1)
 254     {
 255       string remote_host;
 256       u_int16_t remote_port;
 257
 258       plain_packet.setLength(MAX_PACKET_LENGTH);
 259       encrypted_packet.withAuthTag(false);
 260       encrypted_packet.setLength(MAX_PACKET_LENGTH);
 261
 262           // read packet from socket
 263       u_int32_t len = param->src.recv(encrypted_packet.getBuf(), encrypted_packet.getLength(), remote_host, remote_port);
 264       encrypted_packet.setLength(len);
 265
 266       mux_t mux = encrypted_packet.getMux();
 267           // autodetect peer
 268       if(gOpt.getRemoteAddr() == "" && param->cl.empty())
 269       {
 270         cLog.msg(Log::PRIO_NOTICE) << "autodetected remote host " << remote_host << ":" << remote_port;
 271         createConnection(remote_host, remote_port, param->cl, gOpt.getSeqWindowSize(),param->queue,mux);
 272       }
 273
 274       ConnectionMap::iterator cit = param->cl.getConnection(mux);
 275       if (cit == param->cl.getEnd())
 276         continue;
 277       ConnectionParam & conn = cit->second;
 278
 279           // check whether auth tag is ok or not
 280       if(a->getMaxLength()) {
 281         encrypted_packet.withAuthTag(true);
 282         conn.kd_.generate(LABEL_SATP_MSG_AUTH, encrypted_packet.getSeqNr(), session_auth_key);
 283         a->setKey(session_auth_key);
 284         if(!a->checkTag(encrypted_packet)) {
 285           cLog.msg(Log::PRIO_NOTICE) << "wrong Authentication Tag!" << std::endl;
 286           continue;
 287         }
 288         encrypted_packet.removeAuthTag();
 289       }
 290
 291           //Allow dynamic IP changes
 292           //TODO: add command line option to turn this off
 293       if (remote_host != conn.remote_host_ || remote_port != conn.remote_port_)
 294       {
 295         cLog.msg(Log::PRIO_NOTICE) << "connection "<< mux << " autodetected remote host ip changed "
 296                                    << remote_host << ":" << remote_port;
 297         conn.remote_host_=remote_host;
 298         conn.remote_port_=remote_port;
 299         SyncCommand sc (param->cl,mux);
 300         param->queue.push(sc);
 301       }
 302
 303           // Replay Protection
 304       if (!checkPacketSeqNr(encrypted_packet, conn))
 305         continue;
 306
 307           // generate packet-key
 308       conn.kd_.generate(LABEL_SATP_ENCRYPTION, encrypted_packet.getSeqNr(), session_key);
 309       conn.kd_.generate(LABEL_SATP_SALT, encrypted_packet.getSeqNr(), session_salt);
 310       c->setKey(session_key);
 311       c->setSalt(session_salt);
 312
 313           // decrypt packet
 314       c->decrypt(encrypted_packet, plain_packet);
 315
 316           // check payload_type
 317       if((param->dev.getType() == TYPE_TUN && plain_packet.getPayloadType() != PAYLOAD_TYPE_TUN4 &&
 318                                               plain_packet.getPayloadType() != PAYLOAD_TYPE_TUN6) ||
 319          (param->dev.getType() == TYPE_TAP && plain_packet.getPayloadType() != PAYLOAD_TYPE_TAP))
 320         continue;
 321
 322           // write it on the device
 323       param->dev.write(plain_packet.getPayload(), plain_packet.getLength());
 324     }
 325   }
 326   catch(std::exception e)
 327   {
 328     cLog.msg(Log::PRIO_ERR) << "receiver thread died due to an uncaught exception: " << e.what();
 329   }
 330   pthread_exit(NULL);
 331 }
 332
 333 #define MIN_GCRYPT_VERSION "1.2.0"
 334 #if defined(__GNUC__) && !defined(__OpenBSD__) // TODO: thread-safety on OpenBSD
 335 // make libgcrypt thread safe
 336 extern "C" {
 337 GCRY_THREAD_OPTION_PTHREAD_IMPL;
 338 }
 339 #endif
 340
 341 bool initLibGCrypt()
 342 {
 343   // make libgcrypt thread safe
 344   // this must be called before any other libgcrypt call
 345 #if defined(__GNUC__) && !defined(__OpenBSD__) // TODO: thread-safety on OpenBSD
 346   gcry_control( GCRYCTL_SET_THREAD_CBS, &gcry_threads_pthread );
 347 #endif
 348
 349   // this must be called right after the GCRYCTL_SET_THREAD_CBS command
 350   // no other function must be called till now
 351   if( !gcry_check_version( MIN_GCRYPT_VERSION ) ) {
 352     std::cout << "initLibGCrypt: Invalid Version of libgcrypt, should be >= " << MIN_GCRYPT_VERSION << std::endl;
 353     return false;
 354   }
 355
 356   gcry_error_t err = gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
 357   if( err ) {
 358     char buf[NL_TEXTMAX];
 359     std::cout << "initLibGCrypt: Failed to disable secure memory: " << gpg_strerror_r(err, buf, NL_TEXTMAX) << std::endl;
 360     return false;
 361   }
 362
 363   // Tell Libgcrypt that initialization has completed.
 364   err = gcry_control(GCRYCTL_INITIALIZATION_FINISHED);
 365   if( err ) {
 366     char buf[NL_TEXTMAX];
 367     std::cout << "initLibGCrypt: Failed to finish initialization: " << gpg_strerror_r(err, buf, NL_TEXTMAX) << std::endl;
 368     return false;
 369   }
 370
 371   cLog.msg(Log::PRIO_NOTICE) << "initLibGCrypt: libgcrypt init finished";
 372   return true;
 373 }
 374
 375 void chrootAndDrop(std::string const& chrootdir, std::string const& username)
 376 {
 377         if (getuid() != 0)
 378         {
 379           std::cerr << "this programm has to be run as root in order to run in a chroot" << std::endl;
 380                 exit(-1);
 381         }
 382
 383   struct passwd *pw = getpwnam(username.c_str());
 384         if(pw) {
 385                 if(chroot(chrootdir.c_str()))
 386                 {
 387       std::cerr << "can't chroot to " << chrootdir << std::endl;
 388       exit(-1);
 389                 }
 390     cLog.msg(Log::PRIO_NOTICE) << "we are in chroot jail (" << chrootdir << ") now" << std::endl;
 391     chdir("/");
 392                 if (initgroups(pw->pw_name, pw->pw_gid) || setgid(pw->pw_gid) || setuid(pw->pw_uid))
 393                 {
 394                         std::cerr << "can't drop to user " << username << " " << pw->pw_uid << ":" << pw->pw_gid << std::endl;
 395                         exit(-1);
 396                 }
 397     cLog.msg(Log::PRIO_NOTICE) << "dropped user to " << username << " " << pw->pw_uid << ":" << pw->pw_gid << std::endl;
 398         }
 399         else
 400   {
 401     std::cerr << "unknown user " << username << std::endl;
 402     exit(-1);
 403         }
 404 }
 405
 406 void daemonize()
 407 {
 408   pid_t pid;
 409
 410   pid = fork();
 411   if(pid) exit(0);
 412   setsid();
 413   pid = fork();
 414   if(pid) exit(0);
 415
 416 //  std::cout << "running in background now..." << std::endl;
 417
 418   int fd;
 419 //  for (fd=getdtablesize();fd>=0;--fd) // close all file descriptors
 420   for (fd=0;fd<=2;fd++) // close all file descriptors
 421     close(fd);
 422   fd=open("/dev/null",O_RDWR);        // stdin
 423   dup(fd);                            // stdout
 424   dup(fd);                            // stderr
 425   umask(027);
 426 }
 427
 428 int execScript(string const& script, string const& ifname)
 429 {
 430   pid_t pid;
 431   pid = fork();
 432   if(!pid) {
 433     int fd;
 434     for (fd=getdtablesize();fd>=0;--fd) // close all file descriptors
 435       close(fd);
 436     fd=open("/dev/null",O_RDWR);        // stdin
 437     dup(fd);                            // stdout
 438     dup(fd);                            // stderr
 439     return execl("/bin/sh", "/bin/sh", script.c_str(), ifname.c_str(), NULL);
 440   }
 441   int status = 0;
 442   waitpid(pid, &status, 0);
 443   return status;
 444 }
 445
 446 int main(int argc, char* argv[])
 447 {
 448   bool daemonized=false;
 449   try
 450   {
 451
 452 //  std::cout << "anytun - secure anycast tunneling protocol" << std::endl;
 453     if(!gOpt.parse(argc, argv)) {
 454       gOpt.printUsage();
 455       exit(-1);
 456     }
 457
 458     cLog.msg(Log::PRIO_NOTICE) << "anytun started...";
 459
 460     std::ofstream pidFile;
 461     if(gOpt.getPidFile() != "") {
 462       pidFile.open(gOpt.getPidFile().c_str());
 463       if(!pidFile.is_open()) {
 464         std::cout << "can't open pid file" << std::endl;
 465       }
 466     }
 467
 468     TunDevice dev(gOpt.getDevName() =="" ? NULL : gOpt.getDevName().c_str(),
 469                   gOpt.getDevType() =="" ? NULL : gOpt.getDevType().c_str(),
 470                   gOpt.getIfconfigParamLocal() =="" ? NULL : gOpt.getIfconfigParamLocal().c_str(),
 471                   gOpt.getIfconfigParamRemoteNetmask() =="" ? NULL : gOpt.getIfconfigParamRemoteNetmask().c_str());
 472     cLog.msg(Log::PRIO_NOTICE) << "dev created (opened)";
 473     cLog.msg(Log::PRIO_NOTICE) << "dev opened - actual name is '" << dev.getActualName() << "'";
 474     cLog.msg(Log::PRIO_NOTICE) << "dev type is '" << dev.getTypeString() << "'";
 475     if(gOpt.getPostUpScript() != "") {
 476       int postup_ret = execScript(gOpt.getPostUpScript(), dev.getActualName());
 477       cLog.msg(Log::PRIO_NOTICE) << "post up script '" << gOpt.getPostUpScript() << "' returned " << postup_ret;
 478     }
 479
 480
 481 //     Buffer buff(u_int32_t(1600));
 482 //     int len;
 483 //     while(1)
 484 //     {
 485 //       len = dev.read(buff.getBuf(), buff.getLength());
 486 //       std::cout << "read " << len << " bytes from interface " << dev.getActualName() << std::endl;
 487 //       dev.write(buff.getBuf(), len);
 488 //     }
 489
 490 //     return 0;
 491
 492
 493
 494     if(gOpt.getChroot())
 495       chrootAndDrop(gOpt.getChrootDir(), gOpt.getUsername());
 496     if(gOpt.getDaemonize())
 497       daemonize();
 498     daemonized = true;
 499
 500     if(pidFile.is_open()) {
 501       pid_t pid = getpid();
 502       pidFile << pid;
 503       pidFile.close();
 504     }
 505
 506     SignalController sig;
 507     sig.init();
 508
 509     PacketSource* src;
 510     if(gOpt.getLocalAddr() == "")
 511       src = new UDPPacketSource(gOpt.getLocalPort());
 512     else
 513       src = new UDPPacketSource(gOpt.getLocalAddr(), gOpt.getLocalPort());
 514
 515     ConnectionList cl;
 516     ConnectToList connect_to = gOpt.getConnectTo();
 517     SyncQueue queue;
 518
 519     if(gOpt.getRemoteAddr() != "")
 520       createConnection(gOpt.getRemoteAddr(),gOpt.getRemotePort(),cl,gOpt.getSeqWindowSize(), queue, gOpt.getMux());
 521
 522     ThreadParam p(dev, *src, cl, queue,*(new OptionConnectTo()));
 523
 524         // this must be called before any other libgcrypt call
 525     if(!initLibGCrypt())
 526       return -1;
 527
 528     pthread_t senderThread;
 529     pthread_create(&senderThread, NULL, sender, &p);
 530     pthread_t receiverThread;
 531     pthread_create(&receiverThread, NULL, receiver, &p);
 532 #ifndef ANYTUN_NOSYNC
 533     pthread_t syncListenerThread;
 534     if ( gOpt.getLocalSyncPort())
 535       pthread_create(&syncListenerThread, NULL, syncListener, &p);
 536
 537     std::list<pthread_t> connectThreads;
 538     for(ConnectToList::iterator it = connect_to.begin() ;it != connect_to.end(); ++it) {
 539       connectThreads.push_back(pthread_t());
 540       ThreadParam * point = new ThreadParam(dev, *src, cl, queue,*it);
 541       pthread_create(& connectThreads.back(),  NULL, syncConnector, point);
 542     }
 543 #endif
 544
 545     int ret = sig.run();
 546
 547     pthread_cancel(senderThread);
 548     pthread_cancel(receiverThread);
 549 #ifndef ANYTUN_NOSYNC
 550     if ( gOpt.getLocalSyncPort())
 551       pthread_cancel(syncListenerThread);
 552     for( std::list<pthread_t>::iterator it = connectThreads.begin() ;it != connectThreads.end(); ++it)
 553       pthread_cancel(*it);
 554 #endif
 555
 556     pthread_join(senderThread, NULL);
 557     pthread_join(receiverThread, NULL);
 558 #ifndef ANYTUN_NOSYNC
 559     if ( gOpt.getLocalSyncPort())
 560       pthread_join(syncListenerThread, NULL);
 561
 562     for( std::list<pthread_t>::iterator it = connectThreads.begin() ;it != connectThreads.end(); ++it)
 563       pthread_join(*it, NULL);
 564 #endif
 565     delete src;
 566     delete &p.connto;
 567
 568     return ret;
 569   }
 570   catch(std::exception e)
 571   {
 572     if(daemonized)
 573       cLog.msg(Log::PRIO_ERR) << "uncaught exception, exiting: " << e.what();
 574     else
 575       std::cout << "uncaught exception, exiting: " << e.what() << std::endl;
 576   }
 577 }
 578
 579