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
  66   /* Perform the TLS handshake
  67    */
  68   do
  69     {
  70       ret = gnutls_handshake (session);
  71     }
  72   while (ret < 0 && gnutls_error_is_fatal (ret) == 0);
  73
  74   if (ret < 0)
  75     {
  76       fprintf (stderr, "*** Handshake failed\n");
  77       gnutls_perror (ret);
  78       goto end;
  79     }
  80   else
  81     {
  82       printf ("- Handshake was completed\n");
  83     }
  84
  85   gnutls_record_send (session, MSG, strlen (MSG));
  86
  87   ret = gnutls_record_recv (session, buffer, MAX_BUF);
  88   if (ret == 0)
  89     {
  90       printf ("- Peer has closed the TLS connection\n");
  91       goto end;
  92     }
  93   else if (ret < 0)
  94     {
  95       fprintf (stderr, "*** Error: %s\n", gnutls_strerror (ret));
  96       goto end;
  97     }
  98
  99   printf ("- Received %d bytes: ", ret);
 100   for (ii = 0; ii < ret; ii++)
 101     {
 102       fputc (buffer[ii], stdout);
 103     }
 104   fputs ("\n", stdout);
 105
 106   gnutls_bye (session, GNUTLS_SHUT_RDWR);
 107
 108 end:
 109
 110   tcp_close (sd);
 111
 112   gnutls_deinit (session);
 113
 114   gnutls_psk_free_client_credentials (pskcred);
 115
 116   gnutls_global_deinit ();
 117
 118   return 0;
 119 }