doc/examples/ex-client-psk.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 <string.h>
  10 #include <sys/types.h>
  11 #include <sys/socket.h>
  12 #include <arpa/inet.h>
  13 #include <unistd.h>
  14 #include <gnutls/gnutls.h>
  15
  16 /* A very basic TLS client, with PSK authentication.
  17  */
  18
  19 #define MAX_BUF 1024
  20 #define MSG "GET / HTTP/1.0\r\n\r\n"
  21
  22 extern int tcp_connect (void);
  23 extern void tcp_close (int sd);
  24
  25 int
  26 main (void)
  27 {
  28   int ret, sd, ii;
  29   gnutls_session_t session;
  30   char buffer[MAX_BUF + 1];
  31   const char *err;
  32   gnutls_psk_client_credentials_t pskcred;
  33   const gnutls_datum_t key = { (void *) "DEADBEEF", 8 };
  34
  35   gnutls_global_init ();
  36
  37   gnutls_psk_allocate_client_credentials (&pskcred);
  38   gnutls_psk_set_client_credentials (pskcred, "test", &key,
  39                                      GNUTLS_PSK_KEY_HEX);
  40
  41   /* Initialize TLS session
  42    */
  43   gnutls_init (&session, GNUTLS_CLIENT);
  44
  45   /* Use default priorities */
  46   ret = gnutls_priority_set_direct (session, "PERFORMANCE:+ECDHE-PSK:+DHE-PSK:+PSK", &err);
  47   if (ret < 0)
  48     {
  49       if (ret == GNUTLS_E_INVALID_REQUEST)
  50         {
  51           fprintf (stderr, "Syntax error at: %s\n", err);
  52         }
  53       exit (1);
  54     }
  55
  56   /* put the x509 credentials to the current session
  57    */
  58   gnutls_credentials_set (session, GNUTLS_CRD_PSK, pskcred);
  59
  60   /* connect to the peer
  61    */
  62   sd = tcp_connect ();
  63
  64   gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
  65   gnutls_handshake_set_timeout (session, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);
  66
  67   /* Perform the TLS handshake
  68    */
  69   do
  70     {
  71       ret = gnutls_handshake (session);
  72     }
  73   while (ret < 0 && gnutls_error_is_fatal (ret) == 0);
  74
  75   if (ret < 0)
  76     {
  77       fprintf (stderr, "*** Handshake failed\n");
  78       gnutls_perror (ret);
  79       goto end;
  80     }
  81   else
  82     {
  83       printf ("- Handshake was completed\n");
  84     }
  85
  86   gnutls_record_send (session, MSG, strlen (MSG));
  87
  88   ret = gnutls_record_recv (session, buffer, MAX_BUF);
  89   if (ret == 0)
  90     {
  91       printf ("- Peer has closed the TLS connection\n");
  92       goto end;
  93     }
  94   else if (ret < 0)
  95     {
  96       fprintf (stderr, "*** Error: %s\n", gnutls_strerror (ret));
  97       goto end;
  98     }
  99
 100   printf ("- Received %d bytes: ", ret);
 101   for (ii = 0; ii < ret; ii++)
 102     {
 103       fputc (buffer[ii], stdout);
 104     }
 105   fputs ("\n", stdout);
 106
 107   gnutls_bye (session, GNUTLS_SHUT_RDWR);
 108
 109 end:
 110
 111   tcp_close (sd);
 112
 113   gnutls_deinit (session);
 114
 115   gnutls_psk_free_client_credentials (pskcred);
 116
 117   gnutls_global_deinit ();
 118
 119   return 0;
 120 }