doc/examples/ex-serv-x509.c

   1 /* This example code is placed in the public domain. */
   2
   3 #ifdef HAVE_CONFIG_H
   4 #include <config.h>
   5 #endif
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <errno.h>
  10 #include <sys/types.h>
  11 #include <sys/socket.h>
  12 #include <arpa/inet.h>
  13 #include <netinet/in.h>
  14 #include <string.h>
  15 #include <unistd.h>
  16 #include <gnutls/gnutls.h>
  17
  18 #define KEYFILE "key.pem"
  19 #define CERTFILE "cert.pem"
  20 #define CAFILE "/etc/ssl/certs/ca-certificates.crt"
  21 #define CRLFILE "crl.pem"
  22
  23 /* This is a sample TLS 1.0 echo server, using X.509 authentication.
  24  */
  25
  26 #define MAX_BUF 1024
  27 #define PORT 5556               /* listen to 5556 port */
  28
  29 /* These are global */
  30 gnutls_certificate_credentials_t x509_cred;
  31 gnutls_priority_t priority_cache;
  32
  33 static gnutls_session_t
  34 initialize_tls_session (void)
  35 {
  36   gnutls_session_t session;
  37
  38   gnutls_init (&session, GNUTLS_SERVER);
  39
  40   gnutls_priority_set (session, priority_cache);
  41
  42   gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, x509_cred);
  43
  44   /* We don't request any certificate from the client.
  45    * If we did we would need to verify it.
  46    */
  47   gnutls_certificate_server_set_request (session, GNUTLS_CERT_IGNORE);
  48
  49   return session;
  50 }
  51
  52 static gnutls_dh_params_t dh_params;
  53
  54 static int
  55 generate_dh_params (void)
  56 {
  57   int bits = gnutls_sec_param_to_pk_bits (GNUTLS_PK_DH, GNUTLS_SEC_PARAM_LOW);
  58
  59   /* Generate Diffie-Hellman parameters - for use with DHE
  60    * kx algorithms. When short bit length is used, it might
  61    * be wise to regenerate parameters often.
  62    */
  63   gnutls_dh_params_init (&dh_params);
  64   gnutls_dh_params_generate2 (dh_params, bits);
  65
  66   return 0;
  67 }
  68
  69 int
  70 main (void)
  71 {
  72   int listen_sd;
  73   int sd, ret;
  74   struct sockaddr_in sa_serv;
  75   struct sockaddr_in sa_cli;
  76   socklen_t client_len;
  77   char topbuf[512];
  78   gnutls_session_t session;
  79   char buffer[MAX_BUF + 1];
  80   int optval = 1;
  81
  82   /* this must be called once in the program
  83    */
  84   gnutls_global_init ();
  85
  86   gnutls_certificate_allocate_credentials (&x509_cred);
  87   gnutls_certificate_set_x509_trust_file (x509_cred, CAFILE,
  88                                           GNUTLS_X509_FMT_PEM);
  89
  90   gnutls_certificate_set_x509_crl_file (x509_cred, CRLFILE,
  91                                         GNUTLS_X509_FMT_PEM);
  92
  93   ret = gnutls_certificate_set_x509_key_file (x509_cred, CERTFILE, KEYFILE,
  94                                         GNUTLS_X509_FMT_PEM);
  95   if (ret < 0)
  96     {
  97       printf("No certificate or key were found\n");
  98       exit(1);
  99     }
 100
 101   generate_dh_params ();
 102
 103   gnutls_priority_init (&priority_cache, "PERFORMANCE:%SERVER_PRECEDENCE", NULL);
 104
 105
 106   gnutls_certificate_set_dh_params (x509_cred, dh_params);
 107
 108   /* Socket operations
 109    */
 110   listen_sd = socket (AF_INET, SOCK_STREAM, 0);
 111
 112   memset (&sa_serv, '\0', sizeof (sa_serv));
 113   sa_serv.sin_family = AF_INET;
 114   sa_serv.sin_addr.s_addr = INADDR_ANY;
 115   sa_serv.sin_port = htons (PORT);      /* Server Port number */
 116
 117   setsockopt (listen_sd, SOL_SOCKET, SO_REUSEADDR, (void *) &optval,
 118               sizeof (int));
 119
 120   bind (listen_sd, (struct sockaddr *) & sa_serv, sizeof (sa_serv));
 121
 122   listen (listen_sd, 1024);
 123
 124   printf ("Server ready. Listening to port '%d'.\n\n", PORT);
 125
 126   client_len = sizeof (sa_cli);
 127   for (;;)
 128     {
 129       session = initialize_tls_session ();
 130
 131       sd = accept (listen_sd, (struct sockaddr *) & sa_cli, &client_len);
 132
 133       printf ("- connection from %s, port %d\n",
 134               inet_ntop (AF_INET, &sa_cli.sin_addr, topbuf,
 135                          sizeof (topbuf)), ntohs (sa_cli.sin_port));
 136
 137       gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
 138
 139       do
 140         {
 141           ret = gnutls_handshake (session);
 142         }
 143       while (ret < 0 && gnutls_error_is_fatal (ret) == 0);
 144
 145       if (ret < 0)
 146         {
 147           close (sd);
 148           gnutls_deinit (session);
 149           fprintf (stderr, "*** Handshake has failed (%s)\n\n",
 150                    gnutls_strerror (ret));
 151           continue;
 152         }
 153       printf ("- Handshake was completed\n");
 154
 155       /* see the Getting peer's information example */
 156       /* print_info(session); */
 157
 158       for (;;)
 159         {
 160           memset (buffer, 0, MAX_BUF + 1);
 161           ret = gnutls_record_recv (session, buffer, MAX_BUF);
 162
 163           if (ret == 0)
 164             {
 165               printf ("\n- Peer has closed the GnuTLS connection\n");
 166               break;
 167             }
 168           else if (ret < 0)
 169             {
 170               fprintf (stderr, "\n*** Received corrupted "
 171                        "data(%d). Closing the connection.\n\n", ret);
 172               break;
 173             }
 174           else if (ret > 0)
 175             {
 176               /* echo data back to the client
 177                */
 178               gnutls_record_send (session, buffer, strlen (buffer));
 179             }
 180         }
 181       printf ("\n");
 182       /* do not wait for the peer to close the connection.
 183        */
 184       gnutls_bye (session, GNUTLS_SHUT_WR);
 185
 186       close (sd);
 187       gnutls_deinit (session);
 188
 189     }
 190   close (listen_sd);
 191
 192   gnutls_certificate_free_credentials (x509_cred);
 193   gnutls_priority_deinit (priority_cache);
 194
 195   gnutls_global_deinit ();
 196
 197   return 0;
 198
 199 }