doc/examples/ex-client-srp.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 <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 USERNAME "user"
  20 #define PASSWORD "pass"
  21 #define CAFILE "/etc/ssl/certs/ca-certificates.crt"
  22 #define MSG "GET / HTTP/1.0\r\n\r\n"
  23
  24 int main(void)
  25 {
  26         int ret;
  27         int sd, ii;
  28         gnutls_session_t session;
  29         char buffer[MAX_BUF + 1];
  30         gnutls_srp_client_credentials_t srp_cred;
  31         gnutls_certificate_credentials_t cert_cred;
  32
  33         if (gnutls_check_version("3.1.4") == NULL) {
  34                 fprintf(stderr, "GnuTLS 3.1.4 or later is required for this example\n");
  35                 exit(1);
  36         }
  37
  38         /* for backwards compatibility with gnutls < 3.3.0 */
  39         gnutls_global_init();
  40
  41         gnutls_srp_allocate_client_credentials(&srp_cred);
  42         gnutls_certificate_allocate_credentials(&cert_cred);
  43
  44         gnutls_certificate_set_x509_trust_file(cert_cred, CAFILE,
  45                                                GNUTLS_X509_FMT_PEM);
  46         gnutls_srp_set_client_credentials(srp_cred, USERNAME, PASSWORD);
  47
  48         /* connects to server
  49          */
  50         sd = tcp_connect();
  51
  52         /* Initialize TLS session
  53          */
  54         gnutls_init(&session, GNUTLS_CLIENT);
  55
  56
  57         /* Set the priorities.
  58          */
  59         gnutls_priority_set_direct(session,
  60                                    "NORMAL:+SRP:+SRP-RSA:+SRP-DSS",
  61                                    NULL);
  62
  63         /* put the SRP credentials to the current session
  64          */
  65         gnutls_credentials_set(session, GNUTLS_CRD_SRP, srp_cred);
  66         gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, cert_cred);
  67
  68         gnutls_transport_set_int(session, sd);
  69         gnutls_handshake_set_timeout(session,
  70                                      GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);
  71
  72         /* Perform the TLS handshake
  73          */
  74         do {
  75                 ret = gnutls_handshake(session);
  76         }
  77         while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
  78
  79         if (ret < 0) {
  80                 fprintf(stderr, "*** Handshake failed\n");
  81                 gnutls_perror(ret);
  82                 goto end;
  83         } else {
  84                 char *desc;
  85
  86                 desc = gnutls_session_get_desc(session);
  87                 printf("- Session info: %s\n", desc);
  88                 gnutls_free(desc);
  89         }
  90
  91         gnutls_record_send(session, MSG, strlen(MSG));
  92
  93         ret = gnutls_record_recv(session, buffer, MAX_BUF);
  94         if (gnutls_error_is_fatal(ret) != 0 || ret == 0) {
  95                 if (ret == 0) {
  96                         printf
  97                             ("- Peer has closed the GnuTLS connection\n");
  98                         goto end;
  99                 } else {
 100                         fprintf(stderr, "*** Error: %s\n",
 101                                 gnutls_strerror(ret));
 102                         goto end;
 103                 }
 104         } else
 105                 check_alert(session, ret);
 106
 107         if (ret > 0) {
 108                 printf("- Received %d bytes: ", ret);
 109                 for (ii = 0; ii < ret; ii++) {
 110                         fputc(buffer[ii], stdout);
 111                 }
 112                 fputs("\n", stdout);
 113         }
 114         gnutls_bye(session, GNUTLS_SHUT_RDWR);
 115
 116       end:
 117
 118         tcp_close(sd);
 119
 120         gnutls_deinit(session);
 121
 122         gnutls_srp_free_client_credentials(srp_cred);
 123         gnutls_certificate_free_credentials(cert_cred);
 124
 125         gnutls_global_deinit();
 126
 127         return 0;
 128 }