1 files changed, 137 insertions, 0 deletions
diff --git a/doc/examples/ex-client-psk.c b/doc/examples/ex-client-psk.c
new file mode 100644
index 0000000..63ef884
--- /dev/null
+++ b/doc/examples/ex-client-psk.c
@@ -0,0 +1,137 @@
+/* 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 <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <assert.h>
+#include <gnutls/gnutls.h>
+
+/* A very basic TLS client, with PSK authentication.
+ */
+
+#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];
+        const char *err;
+        gnutls_psk_client_credentials_t pskcred;
+        const gnutls_datum_t key = { (void *) "DEADBEEF", 8 };
+
+        if (gnutls_check_version("3.6.3") == NULL) {
+                fprintf(stderr, "GnuTLS 3.6.3 or later is required for this example\n");
+                exit(1);
+        }
+
+        CHECK(gnutls_global_init());
+
+        CHECK(gnutls_psk_allocate_client_credentials(&pskcred));
+        CHECK(gnutls_psk_set_client_credentials(pskcred, "test", &key,
+                                                GNUTLS_PSK_KEY_HEX));
+
+        /* Initialize TLS session
+         */
+        CHECK(gnutls_init(&session, GNUTLS_CLIENT));
+
+        ret =
+            gnutls_set_default_priority_append(session,
+                                         "-KX-ALL:+ECDHE-PSK:+DHE-PSK:+PSK",
+                                         &err, 0);
+
+        /* Alternative for pre-3.6.3 versions:
+         * gnutls_priority_set_direct(session, "NORMAL:+ECDHE-PSK:+DHE-PSK:+PSK", &err)
+         */
+        if (ret < 0) {
+                if (ret == GNUTLS_E_INVALID_REQUEST) {
+                        fprintf(stderr, "Syntax error at: %s\n", err);
+                }
+                exit(1);
+        }
+
+        /* put the x509 credentials to the current session
+         */
+        CHECK(gnutls_credentials_set(session, GNUTLS_CRD_PSK, pskcred));
+
+        /* 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) {
+                fprintf(stderr, "*** Handshake failed\n");
+                gnutls_perror(ret);
+                goto end;
+        } else {
+                char *desc;
+
+                desc = gnutls_session_get_desc(session);
+                printf("- Session info: %s\n", desc);
+                gnutls_free(desc);
+        }
+
+        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_psk_free_client_credentials(pskcred);
+
+        gnutls_global_deinit();
+
+        return 0;
+}