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_system_trust(xcred); */
  88   gnutls_certificate_set_x509_trust_file (x509_cred, CAFILE,
  89                                           GNUTLS_X509_FMT_PEM);
  90
  91   gnutls_certificate_set_x509_crl_file (x509_cred, CRLFILE,
  92                                         GNUTLS_X509_FMT_PEM);
  93
  94   ret = gnutls_certificate_set_x509_key_file (x509_cred, CERTFILE, KEYFILE,
  95                                         GNUTLS_X509_FMT_PEM);
  96   if (ret < 0)
  97     {
  98       printf("No certificate or key were found\n");
  99       exit(1);
 100     }
 101
 102   generate_dh_params ();
 103
 104   gnutls_priority_init (&priority_cache, "PERFORMANCE:%SERVER_PRECEDENCE", NULL);
 105
 106
 107   gnutls_certificate_set_dh_params (x509_cred, dh_params);
 108
 109   /* Socket operations
 110    */
 111   listen_sd = socket (AF_INET, SOCK_STREAM, 0);
 112
 113   memset (&sa_serv, '\0', sizeof (sa_serv));
 114   sa_serv.sin_family = AF_INET;
 115   sa_serv.sin_addr.s_addr = INADDR_ANY;
 116   sa_serv.sin_port = htons (PORT);      /* Server Port number */
 117
 118   setsockopt (listen_sd, SOL_SOCKET, SO_REUSEADDR, (void *) &optval,
 119               sizeof (int));
 120
 121   bind (listen_sd, (struct sockaddr *) & sa_serv, sizeof (sa_serv));
 122
 123   listen (listen_sd, 1024);
 124
 125   printf ("Server ready. Listening to port '%d'.\n\n", PORT);
 126
 127   client_len = sizeof (sa_cli);
 128   for (;;)
 129     {
 130       session = initialize_tls_session ();
 131
 132       sd = accept (listen_sd, (struct sockaddr *) & sa_cli, &client_len);
 133
 134       printf ("- connection from %s, port %d\n",
 135               inet_ntop (AF_INET, &sa_cli.sin_addr, topbuf,
 136                          sizeof (topbuf)), ntohs (sa_cli.sin_port));
 137
 138       gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
 139
 140       do
 141         {
 142           ret = gnutls_handshake (session);
 143         }
 144       while (ret < 0 && gnutls_error_is_fatal (ret) == 0);
 145
 146       if (ret < 0)
 147         {
 148           close (sd);
 149           gnutls_deinit (session);
 150           fprintf (stderr, "*** Handshake has failed (%s)\n\n",
 151                    gnutls_strerror (ret));
 152           continue;
 153         }
 154       printf ("- Handshake was completed\n");
 155
 156       /* see the Getting peer's information example */
 157       /* print_info(session); */
 158
 159       for (;;)
 160         {
 161           memset (buffer, 0, MAX_BUF + 1);
 162           ret = gnutls_record_recv (session, buffer, MAX_BUF);
 163
 164           if (ret == 0)
 165             {
 166               printf ("\n- Peer has closed the GnuTLS connection\n");
 167               break;
 168             }
 169           else if (ret < 0)
 170             {
 171               fprintf (stderr, "\n*** Received corrupted "
 172                        "data(%d). Closing the connection.\n\n", ret);
 173               break;
 174             }
 175           else if (ret > 0)
 176             {
 177               /* echo data back to the client
 178                */
 179               gnutls_record_send (session, buffer, strlen (buffer));
 180             }
 181         }
 182       printf ("\n");
 183       /* do not wait for the peer to close the connection.
 184        */
 185       gnutls_bye (session, GNUTLS_SHUT_WR);
 186
 187       close (sd);
 188       gnutls_deinit (session);
 189
 190     }
 191   close (listen_sd);
 192
 193   gnutls_certificate_free_credentials (x509_cred);
 194   gnutls_priority_deinit (priority_cache);
 195
 196   gnutls_global_deinit ();
 197
 198   return 0;
 199
 200 }