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/* This example code is placed in the public domain. */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <gnutls/gnutls.h>
#include <gnutls/x509.h>
#include "examples.h"
/* A very basic TLS client, with X.509 authentication and server certificate
* verification. Note that error recovery is minimal for simplicity.
*/
#define CHECK(x) assert((x)>=0)
#define MAX_BUF 1024
#define MSG "GET / HTTP/1.0\r\n\r\n"
extern int tcp_connect(void);
extern void tcp_close(int sd);
int main(void)
{
int ret, sd, ii;
gnutls_session_t session;
char buffer[MAX_BUF + 1], *desc;
gnutls_datum_t out;
int type;
unsigned status;
gnutls_certificate_credentials_t xcred;
if (gnutls_check_version("3.4.6") == NULL) {
fprintf(stderr, "GnuTLS 3.4.6 or later is required for this example\n");
exit(1);
}
/* for backwards compatibility with gnutls < 3.3.0 */
CHECK(gnutls_global_init());
/* X509 stuff */
CHECK(gnutls_certificate_allocate_credentials(&xcred));
/* sets the system trusted CAs for Internet PKI */
CHECK(gnutls_certificate_set_x509_system_trust(xcred));
/* If client holds a certificate it can be set using the following:
*
gnutls_certificate_set_x509_key_file (xcred, "cert.pem", "key.pem",
GNUTLS_X509_FMT_PEM);
*/
/* Initialize TLS session */
CHECK(gnutls_init(&session, GNUTLS_CLIENT));
CHECK(gnutls_server_name_set(session, GNUTLS_NAME_DNS, "my_host_name",
strlen("my_host_name")));
/* It is recommended to use the default priorities */
CHECK(gnutls_set_default_priority(session));
/* put the x509 credentials to the current session
*/
CHECK(gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, xcred));
gnutls_session_set_verify_cert(session, "my_host_name", 0);
/* connect to the peer
*/
sd = tcp_connect();
gnutls_transport_set_int(session, sd);
gnutls_handshake_set_timeout(session,
GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);
/* Perform the TLS handshake
*/
do {
ret = gnutls_handshake(session);
}
while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
if (ret < 0) {
if (ret == GNUTLS_E_CERTIFICATE_VERIFICATION_ERROR) {
/* check certificate verification status */
type = gnutls_certificate_type_get(session);
status = gnutls_session_get_verify_cert_status(session);
CHECK(gnutls_certificate_verification_status_print(status,
type, &out, 0));
printf("cert verify output: %s\n", out.data);
gnutls_free(out.data);
}
fprintf(stderr, "*** Handshake failed: %s\n", gnutls_strerror(ret));
goto end;
} else {
desc = gnutls_session_get_desc(session);
printf("- Session info: %s\n", desc);
gnutls_free(desc);
}
/* send data */
CHECK(gnutls_record_send(session, MSG, strlen(MSG)));
ret = gnutls_record_recv(session, buffer, MAX_BUF);
if (ret == 0) {
printf("- Peer has closed the TLS connection\n");
goto end;
} else if (ret < 0 && gnutls_error_is_fatal(ret) == 0) {
fprintf(stderr, "*** Warning: %s\n", gnutls_strerror(ret));
} else if (ret < 0) {
fprintf(stderr, "*** Error: %s\n", gnutls_strerror(ret));
goto end;
}
if (ret > 0) {
printf("- Received %d bytes: ", ret);
for (ii = 0; ii < ret; ii++) {
fputc(buffer[ii], stdout);
}
fputs("\n", stdout);
}
CHECK(gnutls_bye(session, GNUTLS_SHUT_RDWR));
end:
tcp_close(sd);
gnutls_deinit(session);
gnutls_certificate_free_credentials(xcred);
gnutls_global_deinit();
return 0;
}
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