doc/examples/ex-client-resume.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 <string.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <gnutls/gnutls.h>
  11
  12 /* Those functions are defined in other examples.
  13  */
  14 extern void check_alert (gnutls_session_t session, int ret);
  15 extern int tcp_connect (void);
  16 extern void tcp_close (int sd);
  17
  18 #define MAX_BUF 1024
  19 #define CAFILE "ca.pem"
  20 #define MSG "GET / HTTP/1.0\r\n\r\n"
  21
  22 int
  23 main (void)
  24 {
  25   int ret;
  26   int sd, ii;
  27   gnutls_session_t session;
  28   char buffer[MAX_BUF + 1];
  29   gnutls_certificate_credentials_t xcred;
  30
  31   /* variables used in session resuming
  32    */
  33   int t;
  34   char *session_data = NULL;
  35   size_t session_data_size = 0;
  36
  37   gnutls_global_init ();
  38
  39   /* X509 stuff */
  40   gnutls_certificate_allocate_credentials (&xcred);
  41
  42   gnutls_certificate_set_x509_trust_file (xcred, CAFILE, GNUTLS_X509_FMT_PEM);
  43
  44   for (t = 0; t < 2; t++)
  45     {                           /* connect 2 times to the server */
  46
  47       sd = tcp_connect ();
  48
  49       gnutls_init (&session, GNUTLS_CLIENT);
  50
  51       gnutls_priority_set_direct (session, "PERFORMANCE:!ARCFOUR-128", NULL);
  52
  53       gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, xcred);
  54
  55       if (t > 0)
  56         {
  57           /* if this is not the first time we connect */
  58           gnutls_session_set_data (session, session_data, session_data_size);
  59           free (session_data);
  60         }
  61
  62       gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
  63
  64       /* Perform the TLS handshake
  65        */
  66       ret = gnutls_handshake (session);
  67
  68       if (ret < 0)
  69         {
  70           fprintf (stderr, "*** Handshake failed\n");
  71           gnutls_perror (ret);
  72           goto end;
  73         }
  74       else
  75         {
  76           printf ("- Handshake was completed\n");
  77         }
  78
  79       if (t == 0)
  80         {                       /* the first time we connect */
  81           /* get the session data size */
  82           gnutls_session_get_data (session, NULL, &session_data_size);
  83           session_data = malloc (session_data_size);
  84
  85           /* put session data to the session variable */
  86           gnutls_session_get_data (session, session_data, &session_data_size);
  87
  88         }
  89       else
  90         {                       /* the second time we connect */
  91
  92           /* check if we actually resumed the previous session */
  93           if (gnutls_session_is_resumed (session) != 0)
  94             {
  95               printf ("- Previous session was resumed\n");
  96             }
  97           else
  98             {
  99               fprintf (stderr, "*** Previous session was NOT resumed\n");
 100             }
 101         }
 102
 103       /* This function was defined in a previous example
 104        */
 105       /* print_info(session); */
 106
 107       gnutls_record_send (session, MSG, strlen (MSG));
 108
 109       ret = gnutls_record_recv (session, buffer, MAX_BUF);
 110       if (ret == 0)
 111         {
 112           printf ("- Peer has closed the TLS connection\n");
 113           goto end;
 114         }
 115       else if (ret < 0)
 116         {
 117           fprintf (stderr, "*** Error: %s\n", gnutls_strerror (ret));
 118           goto end;
 119         }
 120
 121       printf ("- Received %d bytes: ", ret);
 122       for (ii = 0; ii < ret; ii++)
 123         {
 124           fputc (buffer[ii], stdout);
 125         }
 126       fputs ("\n", stdout);
 127
 128       gnutls_bye (session, GNUTLS_SHUT_RDWR);
 129
 130     end:
 131
 132       tcp_close (sd);
 133
 134       gnutls_deinit (session);
 135
 136     }                           /* for() */
 137
 138   gnutls_certificate_free_credentials (xcred);
 139
 140   gnutls_global_deinit ();
 141
 142   return 0;
 143 }