/* 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 LOOP_CHECK(rval, cmd) \

        do { \

                rval = cmd; \

        } while(rval == GNUTLS_E_AGAIN || rval == GNUTLS_E_INTERRUPTED); \

        assert(rval >= 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, "www.example.com",

                                     strlen("www.example.com")));

        /* 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, "www.example.com", 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 */

        LOOP_CHECK(ret, gnutls_record_send(session, MSG, strlen(MSG)));

        LOOP_CHECK(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;

}