tests/x509self.c

   1 /*
   2  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software
   3  * Foundation, Inc.
   4  *
   5  * Author: Simon Josefsson
   6  *
   7  * This file is part of GnuTLS.
   8  *
   9  * GnuTLS is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 3 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * GnuTLS is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with GnuTLS; if not, write to the Free Software Foundation,
  21  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
  22  */
  23
  24 /* Parts copied from GnuTLS example programs. */
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include <config.h>
  28 #endif
  29
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <sys/types.h>
  34 #if !defined(_WIN32)
  35 #include <netinet/in.h>
  36 #include <sys/socket.h>
  37 #include <sys/wait.h>
  38 #include <arpa/inet.h>
  39 #endif
  40 #include <unistd.h>
  41 #include <gnutls/gnutls.h>
  42
  43 #include "utils.h"
  44
  45 #include "ex-session-info.c"
  46 #include "ex-x509-info.c"
  47 #include "tcp.c"
  48
  49 pid_t child;
  50
  51 static void
  52 tls_log_func (int level, const char *str)
  53 {
  54   fprintf (stderr, "%s |<%d>| %s", child ? "server" : "client", level, str);
  55 }
  56
  57 /* A very basic TLS client, with anonymous authentication.
  58  */
  59
  60
  61 #define MAX_BUF 1024
  62 #define MSG "Hello TLS"
  63
  64 static unsigned char ca_pem[] =
  65   "-----BEGIN CERTIFICATE-----\n"
  66   "MIIB5zCCAVKgAwIBAgIERiYdJzALBgkqhkiG9w0BAQUwGTEXMBUGA1UEAxMOR251\n"
  67   "VExTIHRlc3QgQ0EwHhcNMDcwNDE4MTMyOTExWhcNMDgwNDE3MTMyOTExWjAZMRcw\n"
  68   "FQYDVQQDEw5HbnVUTFMgdGVzdCBDQTCBnDALBgkqhkiG9w0BAQEDgYwAMIGIAoGA\n"
  69   "vuyYeh1vfmslnuggeEKgZAVmQ5ltSdUY7H25WGSygKMUYZ0KT74v8C780qtcNt9T\n"
  70   "7EPH/N6RvB4BprdssgcQLsthR3XKA84jbjjxNCcaGs33lvOz8A1nf8p3hD+cKfRi\n"
  71   "kfYSW2JazLrtCC4yRCas/SPOUxu78of+3HiTfFm/oXUCAwEAAaNDMEEwDwYDVR0T\n"
  72   "AQH/BAUwAwEB/zAPBgNVHQ8BAf8EBQMDBwQAMB0GA1UdDgQWBBTpPBz7rZJu5gak\n"
  73   "Viyi4cBTJ8jylTALBgkqhkiG9w0BAQUDgYEAiaIRqGfp1jPpNeVhABK60SU0KIAy\n"
  74   "njuu7kHq5peUgYn8Jd9zNzExBOEp1VOipGsf6G66oQAhDFp2o8zkz7ZH71zR4HEW\n"
  75   "KoX6n5Emn6DvcEH/9pAhnGxNHJAoS7czTKv/JDZJhkqHxyrE1fuLsg5Qv25DTw7+\n"
  76   "PfqUpIhz5Bbm7J4=\n" "-----END CERTIFICATE-----\n";
  77 const gnutls_datum_t ca = { ca_pem, sizeof (ca_pem) };
  78
  79 static unsigned char cert_pem[] =
  80   "-----BEGIN CERTIFICATE-----\n"
  81   "MIICHjCCAYmgAwIBAgIERiYdNzALBgkqhkiG9w0BAQUwGTEXMBUGA1UEAxMOR251\n"
  82   "VExTIHRlc3QgQ0EwHhcNMDcwNDE4MTMyOTI3WhcNMDgwNDE3MTMyOTI3WjAdMRsw\n"
  83   "GQYDVQQDExJHbnVUTFMgdGVzdCBjbGllbnQwgZwwCwYJKoZIhvcNAQEBA4GMADCB\n"
  84   "iAKBgLtmQ/Xyxde2jMzF3/WIO7HJS2oOoa0gUEAIgKFPXKPQ+GzP5jz37AR2ExeL\n"
  85   "ZIkiW8DdU3w77XwEu4C5KL6Om8aOoKUSy/VXHqLnu7czSZ/ju0quak1o/8kR4jKN\n"
  86   "zj2AC41179gAgY8oBAOgIo1hBAf6tjd9IQdJ0glhaZiQo1ipAgMBAAGjdjB0MAwG\n"
  87   "A1UdEwEB/wQCMAAwEwYDVR0lBAwwCgYIKwYBBQUHAwIwDwYDVR0PAQH/BAUDAweg\n"
  88   "ADAdBgNVHQ4EFgQUTLkKm/odNON+3svSBxX+odrLaJEwHwYDVR0jBBgwFoAU6Twc\n"
  89   "+62SbuYGpFYsouHAUyfI8pUwCwYJKoZIhvcNAQEFA4GBALujmBJVZnvaTXr9cFRJ\n"
  90   "jpfc/3X7sLUsMvumcDE01ls/cG5mIatmiyEU9qI3jbgUf82z23ON/acwJf875D3/\n"
  91   "U7jyOsBJ44SEQITbin2yUeJMIm1tievvdNXBDfW95AM507ShzP12sfiJkJfjjdhy\n"
  92   "dc8Siq5JojruiMizAf0pA7in\n" "-----END CERTIFICATE-----\n";
  93 const gnutls_datum_t cert = { cert_pem, sizeof (cert_pem) };
  94
  95 static unsigned char key_pem[] =
  96   "-----BEGIN RSA PRIVATE KEY-----\n"
  97   "MIICXAIBAAKBgQC7ZkP18sXXtozMxd/1iDuxyUtqDqGtIFBACIChT1yj0Phsz+Y8\n"
  98   "9+wEdhMXi2SJIlvA3VN8O+18BLuAuSi+jpvGjqClEsv1Vx6i57u3M0mf47tKrmpN\n"
  99   "aP/JEeIyjc49gAuNde/YAIGPKAQDoCKNYQQH+rY3fSEHSdIJYWmYkKNYqQIDAQAB\n"
 100   "AoGADpmARG5CQxS+AesNkGmpauepiCz1JBF/JwnyiX6vEzUh0Ypd39SZztwrDxvF\n"
 101   "PJjQaKVljml1zkJpIDVsqvHdyVdse8M+Qn6hw4x2p5rogdvhhIL1mdWo7jWeVJTF\n"
 102   "RKB7zLdMPs3ySdtcIQaF9nUAQ2KJEvldkO3m/bRJFEp54k0CQQDYy+RlTmwRD6hy\n"
 103   "7UtMjR0H3CSZJeQ8svMCxHLmOluG9H1UKk55ZBYfRTsXniqUkJBZ5wuV1L+pR9EK\n"
 104   "ca89a+1VAkEA3UmBelwEv2u9cAU1QjKjmwju1JgXbrjEohK+3B5y0ESEXPAwNQT9\n"
 105   "TrDM1m9AyxYTWLxX93dI5QwNFJtmbtjeBQJARSCWXhsoaDRG8QZrCSjBxfzTCqZD\n"
 106   "ZXtl807ymCipgJm60LiAt0JLr4LiucAsMZz6+j+quQbSakbFCACB8SLV1QJBAKZQ\n"
 107   "YKf+EPNtnmta/rRKKvySsi3GQZZN+Dt3q0r094XgeTsAqrqujVNfPhTMeP4qEVBX\n"
 108   "/iVX2cmMTSh3w3z8MaECQEp0XJWDVKOwcTW6Ajp9SowtmiZ3YDYo1LF9igb4iaLv\n"
 109   "sWZGfbnU3ryjvkb6YuFjgtzbZDZHWQCo8/cOtOBmPdk=\n"
 110   "-----END RSA PRIVATE KEY-----\n";
 111 const gnutls_datum_t key = { key_pem, sizeof (key_pem) };
 112
 113 static void
 114 client (void)
 115 {
 116   int ret, sd, ii;
 117   gnutls_session_t session;
 118   char buffer[MAX_BUF + 1];
 119   gnutls_certificate_credentials_t xcred;
 120
 121   gnutls_global_init ();
 122
 123   gnutls_global_set_log_function (tls_log_func);
 124   if (debug)
 125     gnutls_global_set_log_level (6);
 126
 127   gnutls_certificate_allocate_credentials (&xcred);
 128
 129   /* sets the trusted cas file
 130    */
 131   gnutls_certificate_set_x509_trust_mem (xcred, &ca, GNUTLS_X509_FMT_PEM);
 132   gnutls_certificate_set_x509_key_mem (xcred, &cert, &key,
 133                                        GNUTLS_X509_FMT_PEM);
 134
 135   /* Initialize TLS session
 136    */
 137   gnutls_init (&session, GNUTLS_CLIENT);
 138
 139   /* Use default priorities */
 140   gnutls_set_default_priority (session);
 141
 142   /* put the x509 credentials to the current session
 143    */
 144   gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, xcred);
 145
 146   /* connect to the peer
 147    */
 148   sd = tcp_connect ();
 149
 150   gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
 151
 152   /* Perform the TLS handshake
 153    */
 154   ret = gnutls_handshake (session);
 155
 156   if (ret < 0)
 157     {
 158       fail ("client: Handshake failed\n");
 159       gnutls_perror (ret);
 160       goto end;
 161     }
 162   else if (debug)
 163     {
 164       success ("client: Handshake was completed\n");
 165     }
 166
 167   if (debug)
 168     success ("client: TLS version is: %s\n",
 169              gnutls_protocol_get_name (gnutls_protocol_get_version
 170                                        (session)));
 171
 172   /* see the Getting peer's information example */
 173   if (debug)
 174     print_info (session);
 175
 176   ret = gnutls_record_send (session, MSG, strlen (MSG));
 177
 178   if (ret == strlen (MSG))
 179     {
 180       if (debug)
 181         success ("client: sent record.\n");
 182     }
 183   else
 184     {
 185       fail ("client: failed to send record.\n");
 186       gnutls_perror (ret);
 187       goto end;
 188     }
 189
 190   ret = gnutls_record_recv (session, buffer, MAX_BUF);
 191
 192   if (debug)
 193     success ("client: recv returned %d.\n", ret);
 194
 195   if (ret == GNUTLS_E_REHANDSHAKE)
 196     {
 197       if (debug)
 198         success ("client: doing handshake!\n");
 199       ret = gnutls_handshake (session);
 200       if (ret == 0)
 201         {
 202           if (debug)
 203             success ("client: handshake complete, reading again.\n");
 204           ret = gnutls_record_recv (session, buffer, MAX_BUF);
 205         }
 206       else
 207         {
 208           fail ("client: handshake failed.\n");
 209         }
 210     }
 211
 212   if (ret == 0)
 213     {
 214       if (debug)
 215         success ("client: Peer has closed the TLS connection\n");
 216       goto end;
 217     }
 218   else if (ret < 0)
 219     {
 220       fail ("client: Error: %s\n", gnutls_strerror (ret));
 221       goto end;
 222     }
 223
 224   if (debug)
 225     {
 226       printf ("- Received %d bytes: ", ret);
 227       for (ii = 0; ii < ret; ii++)
 228         {
 229           fputc (buffer[ii], stdout);
 230         }
 231       fputs ("\n", stdout);
 232     }
 233
 234   gnutls_bye (session, GNUTLS_SHUT_RDWR);
 235
 236 end:
 237
 238   tcp_close (sd);
 239
 240   gnutls_deinit (session);
 241
 242   gnutls_certificate_free_credentials (xcred);
 243
 244   gnutls_global_deinit ();
 245 }
 246
 247 /* This is a sample TLS 1.0 echo server, using X.509 authentication.
 248  */
 249
 250 #define SA struct sockaddr
 251 #define MAX_BUF 1024
 252 #define PORT 5556               /* listen to 5556 port */
 253 #define DH_BITS 1024
 254
 255 /* These are global */
 256 gnutls_certificate_credentials_t x509_cred;
 257
 258 static gnutls_session_t
 259 initialize_tls_session (void)
 260 {
 261   gnutls_session_t session;
 262
 263   gnutls_init (&session, GNUTLS_SERVER);
 264
 265   /* avoid calling all the priority functions, since the defaults
 266    * are adequate.
 267    */
 268   gnutls_set_default_priority (session);
 269
 270   gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, x509_cred);
 271
 272   /* request client certificate if any.
 273      Moved to later on to be able to test re-handshakes.
 274      gnutls_certificate_server_set_request (session, GNUTLS_CERT_REQUEST);
 275    */
 276
 277   gnutls_dh_set_prime_bits (session, DH_BITS);
 278
 279   return session;
 280 }
 281
 282 static gnutls_dh_params_t dh_params;
 283
 284 static int
 285 generate_dh_params (void)
 286 {
 287   const gnutls_datum_t p3 = { (char *) pkcs3, strlen (pkcs3) };
 288   /* Generate Diffie-Hellman parameters - for use with DHE
 289    * kx algorithms. These should be discarded and regenerated
 290    * once a day, once a week or once a month. Depending on the
 291    * security requirements.
 292    */
 293   gnutls_dh_params_init (&dh_params);
 294   return gnutls_dh_params_import_pkcs3 (dh_params, &p3, GNUTLS_X509_FMT_PEM);
 295 }
 296
 297 int err, listen_sd, i;
 298 int sd, ret;
 299 struct sockaddr_in sa_serv;
 300 struct sockaddr_in sa_cli;
 301 int client_len;
 302 char topbuf[512];
 303 gnutls_session_t session;
 304 char buffer[MAX_BUF + 1];
 305 int optval = 1;
 306
 307
 308 static unsigned char server_cert_pem[] =
 309   "-----BEGIN CERTIFICATE-----\n"
 310   "MIICVjCCAcGgAwIBAgIERiYdMTALBgkqhkiG9w0BAQUwGTEXMBUGA1UEAxMOR251\n"
 311   "VExTIHRlc3QgQ0EwHhcNMDcwNDE4MTMyOTIxWhcNMDgwNDE3MTMyOTIxWjA3MRsw\n"
 312   "GQYDVQQKExJHbnVUTFMgdGVzdCBzZXJ2ZXIxGDAWBgNVBAMTD3Rlc3QuZ251dGxz\n"
 313   "Lm9yZzCBnDALBgkqhkiG9w0BAQEDgYwAMIGIAoGA17pcr6MM8C6pJ1aqU46o63+B\n"
 314   "dUxrmL5K6rce+EvDasTaDQC46kwTHzYWk95y78akXrJutsoKiFV1kJbtple8DDt2\n"
 315   "DZcevensf9Op7PuFZKBroEjOd35znDET/z3IrqVgbtm2jFqab7a+n2q9p/CgMyf1\n"
 316   "tx2S5Zacc1LWn9bIjrECAwEAAaOBkzCBkDAMBgNVHRMBAf8EAjAAMBoGA1UdEQQT\n"
 317   "MBGCD3Rlc3QuZ251dGxzLm9yZzATBgNVHSUEDDAKBggrBgEFBQcDATAPBgNVHQ8B\n"
 318   "Af8EBQMDB6AAMB0GA1UdDgQWBBTrx0Vu5fglyoyNgw106YbU3VW0dTAfBgNVHSME\n"
 319   "GDAWgBTpPBz7rZJu5gakViyi4cBTJ8jylTALBgkqhkiG9w0BAQUDgYEAaFEPTt+7\n"
 320   "bzvBuOf7+QmeQcn29kT6Bsyh1RHJXf8KTk5QRfwp6ogbp94JQWcNQ/S7YDFHglD1\n"
 321   "AwUNBRXwd3riUsMnsxgeSDxYBfJYbDLeohNBsqaPDJb7XailWbMQKfAbFQ8cnOxg\n"
 322   "rOKLUQRWJ0K3HyXRMhbqjdLIaQiCvQLuizo=\n" "-----END CERTIFICATE-----\n";
 323
 324 const gnutls_datum_t server_cert = { server_cert_pem,
 325   sizeof (server_cert_pem)
 326 };
 327
 328 static unsigned char server_key_pem[] =
 329   "-----BEGIN RSA PRIVATE KEY-----\n"
 330   "MIICXAIBAAKBgQDXulyvowzwLqknVqpTjqjrf4F1TGuYvkrqtx74S8NqxNoNALjq\n"
 331   "TBMfNhaT3nLvxqResm62ygqIVXWQlu2mV7wMO3YNlx696ex/06ns+4VkoGugSM53\n"
 332   "fnOcMRP/PciupWBu2baMWppvtr6far2n8KAzJ/W3HZLllpxzUtaf1siOsQIDAQAB\n"
 333   "AoGAYAFyKkAYC/PYF8e7+X+tsVCHXppp8AoP8TEZuUqOZz/AArVlle/ROrypg5kl\n"
 334   "8YunrvUdzH9R/KZ7saNZlAPLjZyFG9beL/am6Ai7q7Ma5HMqjGU8kTEGwD7K+lbG\n"
 335   "iomokKMOl+kkbY/2sI5Czmbm+/PqLXOjtVc5RAsdbgvtmvkCQQDdV5QuU8jap8Hs\n"
 336   "Eodv/tLJ2z4+SKCV2k/7FXSKWe0vlrq0cl2qZfoTUYRnKRBcWxc9o92DxK44wgPi\n"
 337   "oMQS+O7fAkEA+YG+K9e60sj1K4NYbMPAbYILbZxORDecvP8lcphvwkOVUqbmxOGh\n"
 338   "XRmTZUuhBrJhJKKf6u7gf3KWlPl6ShKEbwJASC118cF6nurTjuLf7YKARDjNTEws\n"
 339   "qZEeQbdWYINAmCMj0RH2P0mvybrsXSOD5UoDAyO7aWuqkHGcCLv6FGG+qwJAOVqq\n"
 340   "tXdUucl6GjOKKw5geIvRRrQMhb/m5scb+5iw8A4LEEHPgGiBaF5NtJZLALgWfo5n\n"
 341   "hmC8+G8F0F78znQtPwJBANexu+Tg5KfOnzSILJMo3oXiXhf5PqXIDmbN0BKyCKAQ\n"
 342   "LfkcEcUbVfmDaHpvzwY9VEaoMOKVLitETXdNSxVpvWM=\n"
 343   "-----END RSA PRIVATE KEY-----\n";
 344
 345 const gnutls_datum_t server_key = { server_key_pem,
 346   sizeof (server_key_pem)
 347 };
 348
 349 static void
 350 server_start (void)
 351 {
 352   /* Socket operations
 353    */
 354   listen_sd = socket (AF_INET, SOCK_STREAM, 0);
 355   if (err == -1)
 356     {
 357       perror ("socket");
 358       fail ("server: socket failed\n");
 359       return;
 360     }
 361
 362   memset (&sa_serv, '\0', sizeof (sa_serv));
 363   sa_serv.sin_family = AF_INET;
 364   sa_serv.sin_addr.s_addr = INADDR_ANY;
 365   sa_serv.sin_port = htons (PORT);      /* Server Port number */
 366
 367   setsockopt (listen_sd, SOL_SOCKET, SO_REUSEADDR, (void *) &optval,
 368               sizeof (int));
 369
 370   err = bind (listen_sd, (SA *) & sa_serv, sizeof (sa_serv));
 371   if (err == -1)
 372     {
 373       perror ("bind");
 374       fail ("server: bind failed\n");
 375       return;
 376     }
 377
 378   err = listen (listen_sd, 1024);
 379   if (err == -1)
 380     {
 381       perror ("listen");
 382       fail ("server: listen failed\n");
 383       return;
 384     }
 385
 386   if (debug)
 387     success ("server: ready. Listening to port '%d'.\n", PORT);
 388 }
 389
 390 static void
 391 server (void)
 392 {
 393   /* this must be called once in the program
 394    */
 395   gnutls_global_init ();
 396
 397   gnutls_global_set_log_function (tls_log_func);
 398   if (debug)
 399     gnutls_global_set_log_level (6);
 400
 401   gnutls_certificate_allocate_credentials (&x509_cred);
 402   gnutls_certificate_set_x509_trust_mem (x509_cred, &ca, GNUTLS_X509_FMT_PEM);
 403
 404   gnutls_certificate_set_x509_key_mem (x509_cred, &server_cert, &server_key,
 405                                        GNUTLS_X509_FMT_PEM);
 406
 407   if (debug)
 408     success ("Launched, generating DH parameters...\n");
 409
 410   generate_dh_params ();
 411
 412   gnutls_certificate_set_dh_params (x509_cred, dh_params);
 413
 414   client_len = sizeof (sa_cli);
 415
 416   session = initialize_tls_session ();
 417
 418   sd = accept (listen_sd, (SA *) & sa_cli, &client_len);
 419
 420   if (debug)
 421     success ("server: connection from %s, port %d\n",
 422              inet_ntop (AF_INET, &sa_cli.sin_addr, topbuf,
 423                         sizeof (topbuf)), ntohs (sa_cli.sin_port));
 424
 425   gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
 426   ret = gnutls_handshake (session);
 427   if (ret < 0)
 428     {
 429       close (sd);
 430       gnutls_deinit (session);
 431       fail ("server: Handshake has failed (%s)\n\n", gnutls_strerror (ret));
 432       return;
 433     }
 434   if (debug)
 435     {
 436       success ("server: Handshake was completed\n");
 437       success ("server: TLS version is: %s\n",
 438                gnutls_protocol_get_name (gnutls_protocol_get_version
 439                                          (session)));
 440     }
 441
 442   /* see the Getting peer's information example */
 443   if (debug)
 444     print_info (session);
 445
 446   i = 0;
 447   for (;;)
 448     {
 449       memset (buffer, 0, MAX_BUF + 1);
 450       ret = gnutls_record_recv (session, buffer, MAX_BUF);
 451
 452       if (ret == 0)
 453         {
 454           if (debug)
 455             success ("server: Peer has closed the GnuTLS connection\n");
 456           break;
 457         }
 458       else if (ret < 0)
 459         {
 460           fail ("server: Received corrupted data(%d). Closing...\n", ret);
 461           break;
 462         }
 463       else if (ret > 0)
 464         {
 465           gnutls_certificate_server_set_request (session,
 466                                                  GNUTLS_CERT_REQUEST);
 467
 468           if (debug)
 469             success ("server: got data, forcing rehandshake.\n");
 470
 471           ret = gnutls_rehandshake (session);
 472           if (ret < 0)
 473             {
 474               fail ("server: rehandshake failed\n");
 475               gnutls_perror (ret);
 476               break;
 477             }
 478
 479           ret = gnutls_handshake (session);
 480           if (ret < 0)
 481             {
 482               fail ("server: (re)handshake failed\n");
 483               gnutls_perror (ret);
 484               break;
 485             }
 486
 487           if (debug)
 488             success ("server: rehandshake complete.\n");
 489
 490           /* echo data back to the client
 491            */
 492           gnutls_record_send (session, buffer, strlen (buffer));
 493         }
 494     }
 495   /* do not wait for the peer to close the connection.
 496    */
 497   gnutls_bye (session, GNUTLS_SHUT_WR);
 498
 499   close (sd);
 500   gnutls_deinit (session);
 501
 502   close (listen_sd);
 503
 504   gnutls_certificate_free_credentials (x509_cred);
 505
 506   gnutls_dh_params_deinit (dh_params);
 507
 508   gnutls_global_deinit ();
 509
 510   if (debug)
 511     success ("server: finished\n");
 512 }
 513
 514
 515 void
 516 doit (void)
 517 {
 518   /* parent */
 519   server_start ();
 520   if (error_count)
 521     return;
 522
 523   child = fork ();
 524   if (child < 0)
 525     {
 526       perror ("fork");
 527       fail ("fork");
 528       return;
 529     }
 530
 531   if (child)
 532     {
 533       int status;
 534
 535       server ();
 536       wait (&status);
 537     }
 538   else
 539     client ();
 540 }